From: gazissax@netcom.com Newsgroups: misc.kids.info,misc.answers,news.answers Subject: misc.kids FAQ on Childhood Vaccinations, Part 3/4 Followup-To: misc.kids.health Approved: news-answers-request@MIT.EDU, kids-info-request@ai.mit.edu Reply-To: gazissax@netcom.com Summary: This FAQ contains information on vaccinations, with particular focus on the vaccinations given to children. Section 3 contains information about vaccines which are not on the required schedule for children within the USA (though some may be required in other countries), or which have been added since 1996. These include travel vaccines, vaccines which are not yet approved, and vaccines which, within the USA, are given only to people with particular risk factors. Archive-name: misc-kids/vaccinations/part3 Posting-Frequency: monthly Last-Modified: October 23, 1999===============================================================================
Q3f.1 What is influenza, and what are the risks of the disease?
Influenza has a fairly high mortality rate among the elderly and the
chronically ill. Complications include pneumonia, neurological
complications, myocardia, heart block, and peripheral vasoconstriction.
Q3f.2 How common is influenza?
Outbreaks of flu occur almost every year, generally in the winter,
and can cause thousands to be hospitalized.
Q3f.3 How effective is the influenza vaccine?
About 70-80% in young, healthy adults. About 50% effective in adults
over 60. (For studies on older adults, see JAMA 1994 Dec 7,
N Engl J Med 1994.) For a summary of recent studies showing benefits
in elderly adults, young children in day care, and healthy adults,
see Journal Watch for January 1, 1996, Volume 16, Number 1, "Top Medical
Stories of 1995." Of particular interest to parents is a study published
in Arch Pediatr Adolesc Medicine, Oct 1995, 149:1113, in which children
at high risk for otitis media (ear infections) showed 32% fewer cases
during the flu season when they received the flu vaccine.
Note that influenza vaccine protects against influenza only, and not
against other respiratory infections.
An intranasal flu vaccine has shown efficacy in trials and may be
available within a year.
Q3f.4 How long does the influenza vaccine last?
It has to be repeated every year, as the strains of influenza vary
from year to year.
Q3f.5 What are some of the risks of the influenza vaccine?
Public confidence in flu shots was reduced by the swine flu controversy
of 1976-1977. Of the nearly 48 million people who were vaccinated
that year, about 500 came down with a rare paralytic condition called
Guillaine-Barre syndrome. This was many more than could normally be
expected to come down with this disease (though still a small percentage
of all the vaccinated people). After this year, there were changes to
the vaccine, and medical sources (Berkeley, PDR) report that the vaccine
has not been clearly associated with Guillaine-Barr syndrome since that
time.
Adverse reactions include local tenderness, and, infrequently, fever,
"most often [affecting] people who have had no exposure to the
influenza virus antigens in the vaccine (e.g. small children)." (PDR)
Allergic reactions also occur.
Q3f.6 When is the influenza vaccine recommended?
It is recommended for people who are over 65 and for people with
various chronic illnesses, particularly those affecting the lungs
(including asthma) or the heart. Candidates among children include
similar groups to those for pneumococcal vaccine: sickle cell, chronic
renal and metabolic disease, diabetes, chronic pulmonary disease,
long-term aspirin therapy, and significant cardiac disease (Catalana).
In the US, the rate of vaccination for influenza in the groups for
whom the vaccine is recommended is only 20%. Among children, the
rate is 1-7% (Catalana).
The antiviral drugs amantadine and rimantadine are also effective against
influenza A, but not influenza B.
Q3f.7 When is the influenza vaccine contraindicated?
Egg allergy, hypersensitivity to thimerosal. Delay in case of an
active neurological disease or fever. (PDR) The AHFS gives the
same contraindications, but adds a history of Guillaine-Barre
syndrome and bleeding disorders which would contraindicate
intramuscular injection.
Vaccine components capable of causing adverse reactions: chick embryo
components, formaldehyde, thimerosal (Travel Medicine Advisor).
Q3f.8 Is it OK to be vaccinated for influenza during pregnancy?
It depends. When this topic has come up on misc.kids, people have
reported different recommendations from their doctors. And, when I
consulted the PDR, I found the same result: the PDR says that the
risks of the vaccine (especially during the first trimester) have to
be weighed against the risks of a particular patient getting the flu,
and that "The clinical judgment of the attending physician should
prevail at all times in determining whether to administer the vaccine
to a pregnant woman."
The CDC, in the October 8, 1999 issue of MMWR, recommended
that "Pregnant women with high-risk medical conditions should be
vaccinated before the start of the influenza season regardless of
their stage of pregnancy. Pregnant women without high-risk medical
conditions, but who will be in their second or third trimester during the
influenza season, are at elevated risk of complications and should be
vaccinated. Some experts prefer to vaccinate these women during the
second trimester to avoid a coincidental association with spontaneous
abortion, which is common in the first trimester, and because exposures
to vaccines traditionally have been avoided during the first trimester. "
===============================================================================
Q3g.1 What is pneumococcal disease, and what are the risks of the
disease?
It causes ear infections and sinusitis in children, and sometimes
meningitis and pneumonia.
Q3g.2 How common is pneumococcal disease?
Q3g.3 How effective is the pneumococcal vaccine?
It protects against 23 strains of pneumococcus, 85% of those which cause
ear infections and almost all of those which cause pneumonia and
meningitis. Harrison's Internal Medicine estimates its effectiveness at
60-80%.
Some recent articles discussing (and debating about) the effectiveness of
pneumococcal vaccine can be found in Arch Intern Med 1994 Dec; 154:373,
154:2666 and 154:2531; these articles and others are summarized in "Feature:
Does Pneumococcal Vaccine Live Up to Its Reputation?" in the February 28,
1995 Journal Watch (electronic form) or Mar 1, 1995 Journal Watch (print
form). Other relevant articles are in the Annals of Internal Medicine
1988;108:616-625 and the New England Journal of Medicine for 11/21/91.
Q3g.4 How long does the pneumococcal vaccine last?
According to a chart I got from Kaiser, one dose is good for life, except
for immune suppressed or immunodeficient patients, who should get a
booster two years later. _Travel Medicine Advisor_ also says that no
booster is required. _AHFS Drug Information_, however, says that
antibodies are elevated at least five years in healthy adults, but decline
to prevaccination levels after ten years in some.
The reason for the apparent conflict in recommendations is that allergic
reactions are more common after the booster shots, but, at the same time,
the booster shots are useful for maintaining immunity. For this reason,
there has been some debate about the booster shots; the most recent
recommendation is "revaccination with pneumococcal vaccine after six years
in people with high-risk chronic conditions" (Journal Watch for Oct 18,
1994). (An example is a person without a functioning spleen.) The
23-valent vaccine was introduced in 1993; prior to that the vaccine was
only 14-valent.
Journal Watch for Oct 18, 1994 summarizes an article in the Archives of
Internal Medicine (1994 Oct 10; 154:2209-14) on pneumococcal boosters.
"Antibody levels wane significantly within six years after vaccination,
necessitating revaccination of high-risk patients. This interesting study
evaluated immunogenicity associated with revaccination." Shots of
pneumococcal vaccine were found to increase antibody levels "at least
1.4-fold in about 55 percent" of both previously unvaccinated adults and
those who had been vaccinated 5.5 to 9 years previously.
Q3g.5 What are some of the risks of the pneumococcal vaccine?
Discomfort at injection in 30-40% of recipients, and fever in 5-20% of
recipients. (Catalana)
Q3g.6 When is the pneumococcal vaccine recommended?
It is recommended for children 2 or older who are at increased risk of
pneumococcal infection. Conditions which increase risk of pneumoccoal
infection include HIV positive status, functional or anatomic asplenia,
and sickle cell or other hemoglobinopathies. It is also recommended for
adults 65 or older and adults with significant cardiovascular or
pulmonary disorders, splenic dysfunction, asplenia, Hodgkin's Disease,
multiple myeloma, cirrhosis, alcoholism, renal failure, CSF leaks, or
immunosuppressive conditions.
Work is underway now to develop and test a pneumococcal conjugate vaccine
(analogous to the HiB conjugate vaccine) to allow immunization of those
younger than 24 months (which is the age group most affected by S.
pneumoniae). This might open up a new indication for pneumococcal vaccine:
prevention of middle ear infections. As of 1997, four different conjugate
pneumococcal vaccines for infants were in Phase II/III trials (Williams, 1997)
Q3g.7 When is the pneumococcal vaccine contraindicated?
It should not be given to children under 2. It also shouldn't be given
to people who have already been vaccinated (except for booster shots for
those in the highest risk categories).
Vaccine components capable of causing adverse reactions: phenol,
polysaccharides, thimerosal (Travel Medicine Advisor).
===============================================================================
Q3h.1 What is meningococcal disease, and what are the risks of the
disease?
Meningococcal disease is a rare disease which causes meningitis as well
as widespread blood infection, leading to shock and death.
Q3h.2 How common is meningococcal disease?
About 2,500 cases a year in the US, but tens of thousands annually in
sub-Saharan Africa.
Q3h.3 How effective is the meningococcal vaccine?
The current vaccine not highly immunogenic in children under 2,
or very long lasting, and it is children under 2 who have
the highest rate of the disease. Research is being done on conjugate
vaccines which would produce a greater immune response.
Global cooperation would be needed to make these affordable
in developing countries. (Williams, 1997)
Q3h.4 How long does the meningococcal vaccine last?
I don't have this information.
Q3h.5 What are some of the risks of the meningococcal vaccine?
Adverse reactions are infrequent and mild, mostly redness at the
injection site for 1-2 days. Up to 2% of children vaccinated will
experience transient fever (Health Information for the International
Traveller, 1992).
Q3h.6 When is the meningococcal vaccine recommended?
For children with certain types of immune disorders and during epidemic
outbreaks. It is also given to children travelling to certain areas,
and is required for pilgrims to Mecca for the annual Haj (as of 1992,
according to the CDC).
Q3h.7 When is the meningococcal vaccine contraindicated?
I haven't found any, except pregnancy (when it should be given only
in case of an outbreak).
Vaccine components capable of causing adverse reactions: phenol,
polysaccharides, thimerosal (Travel Medicine Advisor).
===============================================================================
[Note: The varicella section has been modified slightly and updated.
Information is from FDA press releases on 1/28/94 and 3/17/95 and
and an article in Infectious Diseases in Children newsletter {vol
8(2) February l995}. It has been further updated based on the
July 12, 1996 recommendation by ACIP. This section last updated
on September 25, 1999. I have some additional information on zoster
which I will be merging into this section in my next update.]
Q3i.1 What is chicken pox, and what are the risks of the disease?
Varicella or chickenpox is a highly contagious disease caused by varicella
zoster virus. Complications are rare in normal children, but more common
in children with immune deficiencies. The disease is somewhat more severe
in adults, and can be serious for newborns and pregnant women. Possible
(infrequent) complications include hemorrhagic varicella, encephalitis,
pneumonia, and bacterial skin infection. Possible complications in
pregnancy include premature birth and congenital varicella, and mortality
(of the infant, not the mother) is high. "It is estimated that there are
about 9,600 chicken-pox related hospitalizations annually, with 50 to 100
deaths." (FDA announcement, January 28, 1994) Another risk, unfortunately
on the increase, is invasive group A streptococcal infections, to which
children ill with varicella may be susceptible.
A study of the effects of congenital varicella and herpes zoster
(Enders G; et al. Consequences of varicella and herpes zoster in
pregnancy: prospective study of 1739 cases. Lancet 1994 Jun 18;
343:1548-51., summarized in Journal Watch Summaries for July 1,
1994.) followed 1373 women with varicella and 366 women with
herpes zoster acquired during the first 36 weeks of pregnancy.
Nine of the infants had congenital varicella syndrome, with
defects ranging from "multisystem involvement to limb hypoplasia
and skin scars." There were no cases of congenital varicella
syndrome among infants whose mothers had varicella after 20 weeks
or among those whose mothers received anti-varicella-zoster
immunoglobulin after they were exposed.
Q3i.2 How common is chicken pox?
An estimated 3.7 million Americans are affected by chickenpox
each year, with more than 90% of the cases occurring in persons
under 15 years of age. 33% of cases are estimated to occur in
children ages 1 to 4, and 44% in children ages 5 to 9 (estimates
from January 28, 1994 FDA announcement).
In tropical regions, chicken pox is less common, and many people
may reach adulthood without immunity (adult immigrants from tropical
to temperate regions may therefore be at risk).
I do not have data on how varicella incidence has been affected
by the availability of the vaccine, but vaccine coverage is
still (as of 1999) fairly low for this particular vaccine.
Q3i.3 What is Herpes Zoster?
Following chickenpox infection, the varicella zoster virus
persists in a latent form in sensory nerve ganglia without any
signs of illness. The virus can be reactivated causing herpes
zoster or shingles, which is a painful small blister-like rash in
the distribution of one or more sensory nerve roots. It is
estimated that 15% of the population will experience zoster
during their lifetimes. Zoster develops most frequently among
the elderly and among individuals who are immunocompromised.
Most people only have one episode of herpes zoster; fewer than
4% will have repeated episodes. Postherpetic neuralgia is a
common complication; this complication is more common among
the elderly (25-50% of those over 50 who have shingles, but only
10% of all people who have shingles.
(Information on the effect of the vaccine on herpes zoster will
be added to this FAQ later.)
Q3i.4 What is the current recommendation for the chicken pox
vaccine be part for children?
The chickenpox (varicella) vaccine was first licensed for use
among high-risk children in several European countries in 1984,
in Japan in 1986, and in Korea in 1988. It has been used for
healthy children in Japan and Korea since 1989. This vaccine was
licensed by FDA on March 17, l995. It is manufactured by Merck
and Co. Inc. under the trade name "Varivax." On July 12, 1996,
ACIP came out with its recommendations for the new vaccine.
ACIP recommends that all children be routinely vaccinated at
12-18 months of age. The American Academy of Pediatrics recommends
that it be given to everyone over the age of one who is not already
immune to chicken pox. Currently it is approved by the FDA for a
single injection in children ages 12 months to 12 years, and two
injections 4-8 weeks apart for adolescents and adults--ages 13 and
older-- who have not contracted chickenpox. Since the vaccine has
been shown to be safe and effective when given at the same time as
measles, mumps and rubella vaccines, it is likely many physicians
will give it either at the 12 or 15 month checkup. Research is
underway for development of a combination measles, mumps, rubella and
varicella vaccine to avoid the need for a second injection. It is
unknown when this product may become licensed.
Q3i.5 What is the current recommendation for adults?
Q3i.6 How effective is the chicken pox vaccine?
Clinical trials, which span a decade and involved more than
11,000 persons in the United States, indicate that it is 70-90
percent effective in preventing chickenpox. Studies also show
that almost all of the vaccinated patients who got chickenpox had
a milder form of the disease.
Q3i.7 How long does the chicken pox vaccine last?
We don't know yet. It is estimated to last at least six years. (Lancet,
April 16, 1994) "Children immunized as long as six years earlier continued
to be well protected. . . . So far, the US data show persistence of
antibodies for three to four years after immunization; data from Japan
show persistence of antibodies for seven to 10 years in healthy children."
(Gershon)
Q3i.8 What reactions have been reported following the chickenpox
vaccine?
Adverse reactions reported were mild and included redness,
hardness and swelling at the injection site, fatigue, malaise and
nausea. The vaccine has been used in Japan routinely for more
than 10 years with no complications.
Q3i.9 Will a second dose be necessary in younger children?
The question of a "booster" dose remains uncertain at this point.
The manufacturer has agreed to perform postmarketing studies to
determine the long-term effects of the vaccine and whether there
is a need for a booster immunization.
Q3i.10 For which groups is the chicken pox vaccine especially
recommended?
People with HIV, nephrosis, severe asthma, and similar chronic
diseases, but especially leukemia. Conditions for vaccination of
leukemic children are: remission for at least a year, off maintenance
therapy for a week before and a week after getting the vaccine, and
cellular immunity intact. (Catalana)
Q3i.11 When is the chicken pox vaccine contraindicated?
Although no adverse reactions from taking aspirin after the vaccine have
been reported, it is recommended that people receiving the varicella
vaccine refrain from taking aspirin for 6 weeks afterwards, because of
the association between aspirin and Reyes syndrome following varicella.
Q3i.12 Is there a gamma globulin for chicken pox?
Yes, but it is only available to people at especially high risk from
chicken pox. It needs to be given within 72 hours of exposure. More
common on misc.kids is the concern of adults who haven't had chicken pox,
but aren't otherwise at high risk from exposure. The varicella immune
globulin isn't likely to be available to these people, but something else
is available: acyclovir. This antiviral drug will lessen the severity of
chicken pox if it is given promptly, as soon as the rash first begins to
appear.
===============================================================================
Q3j.1 What is tuberculosis, and what are the risks of the disease?
Tuberculosis is a chronic bacterial infection that is spread by inhaling
droplets sprayed into the air by someone infected with TB (it can also be
spread through unpasteurized milk). It isn't as contagious as a cold
(you need to inhale a higher concentration of the droplets to catch it).
The disease most commonly affects the lungs, the bones of the spine or
large joints, and the kidneys, but can reach almost any organ of the body.
Q3j.2 How common is tuberculosis?
In 1930, mortality was 101.5 per 100,000 population in the US. It
declined steadily, and in 1970 was 18.3 per 100,1000 population
(Historical Statistics). 37.1 thousand cases were reported in 1970, and
the number was down to 25.7 thousand in 1990 (Statistical Abstracts).
Unfortunately, while that number represents a decrease from 1970,
it represents an *increase* from 1985. In 1985, after decades of
decline, TB cases began to rise again in the US, and have continued
to rise ever since. A similar increase has occurred in several
other industrialized countries (TB was never really brought under
control in the Third World). Moreover, new, multi-drug-resistant
strains of TB have emerged. The AIDS epidemic has worsened the TB
situation. (Ryan) The percentage of cases of drug-resistant TB varies
in different areas. A Morbidity and Mortality Weekly Report article
summarized in the June 15, 1994 HICN726 Medical News gives the incidence
overall in New Jersey as 5% of the state's TB patients, the incidence in
Jersey City as 13%, and the incidence in New York City as 19%.
A joint statement by ACIP and the Advisory Council for the Elimination
of Tuberculosis, published in MMWR, Volume 45, No. RR-4, April 26, 1996
states that the incidence of TB declined through 1984, increased from
1985 through 1992, and declined slightly in 1993 and 1994. 57% of
the total number of TB cases were reported in five states: California,
New York, Florida, Illinois, and Texas. Overall incidence rates are twice
as high for men as for women.
Q3j.3 How effective is the BCG vaccine?
The AHFS Drug Information, 1992 says that its effectiveness is unknown,
"Diagnostic and clinical evidence has generally demonstrated a reduction`
in the incidence of tuberculosis." Tuberculin sensitivity is highly
variable, depending on the strain, and the relationship between tuberculin
sensitivity and immunity has not been adequately studied.
_The Forgotten Plague_ says that results of research varied in different
countries. In Great Britain, a Medical Research Council survey of
50,000 children showed an 80% reduction in the infection rate after
vaccination, leading Great Britain to introduce BCG vaccination of
school children in the 1950s. In the US, the results were the opposite,
so the US has not used the vaccine.
A New York Times article ("Tuberculosis Vaccine Found Surprisingly
Effective in Studies", New York Times, 03/02/94, P. C14), recently
reported that "A new statistical study by the Centers for Disease
Control and Prevention reports that the vaccine, known as BCG,
reduced the risk of full-fledged tuberculosis of the lung by 50
percent and death by 71 percent." A study reported in J Infect Dis in
August 1994 concluded that BCG vaccine is effective, but local reactions
are common.
The joint ACIP and ACET report in the April 26, 1996 MMWR says that there
are different strains of BCG vaccine in use worldwide, and they differ
in their ability to induce an immune response to tuberculin. Reported
rates of efficacy may also have been affected by methods of vaccine
administration and the characteristics and environment of the populations
to which the vaccine was given. Protective efficacy rates for different
studies of different BCG strains have ranged from 0% to 80%. Two recent
meta-analyses of the published literature have attempted to calculate
summary estimates of efficacy. The first analyzed data from 10 randomized
clinical trials and 8 case-control studies since 1950. It estimated
protective efficacy against meningeal and miliary TB in children in
clinical trials as 88%, and the efficacy in case-control studies as 75%.
There was too much variability in data on efficacy against pulmonary
TB for them to come up with a summary efficacy rate. The second
meta-analysis reviewed 14 clinical trials and 12 case-control studies.
They estimated the overall efficacy of the vaccine in clinical trials
to be 51%, with higher efficacy for children than for adults.
Q3j.4 How long does the BCG vaccine last?
It is of limited duration (Ryan). _AHFS Drug Information_ says that
several studies showed tuberculin sensitivity lasting 7-10 years.
Q3j.5 What are some of the risks of the BCG vaccine?
It rarely has serious side effects. (See _AHFS Drug Information_
for a list.) The most common reactions are local. More severe local
reactions include ulceration at the vaccination site, regional
lymphadenitis with draining sinuses, and purulent drainage at
the puncture site. The most serious reaction is disseminated BCG
infection; BCG osteitis of the epiphyses of the long bones, particularly
epiphyses of the legs, can occur from 4 months to 2 years after
vaccination. The rate varies from 0.01 cases per million vaccinees,
in Japan, to 32.5 and 43.4 cases per million vaccinees, in Sweden
and Finland, respectively. Reactions may be more frequent among
people with symptomatic HIV infection.
BCG vaccine is given in developing countries because it is easy to
administer, inexpensive, and rarely has serious side effects.
Some industrialized countries (e.g. Great Britain, France, Scandinavia)
have also used it, for vaccination of children in general and of
household contacts of people with TB. Others (e.g. the US, the
Netherlands) have not.
Because of the low rate of new infections, the availability of low-cost
isoniazid prophylaxis for people who are exposed, and the availability
of effective treatment which quickly make patients non-contagious and
cures them, the BCG vaccine hasn't been considered necessary in the US.
There might be some changes in these recommendations with the increase in
multiple-drug-resistant strains (one misc.kids poster reports that her city
college system is now requiring TB shots). In the meantime, the FDA has
approved a new combination tuberculosis drug, Rifater, which combines
isoniazid, rifampin, and pyrazinamide, in hopes of making it easier for
patients to take their medication and thus increasing patient compliance
(antibiotic treatment which is discontinued too early increases the development
of drug resistant TB strains).
In the US, the AAP, ACIP, and the American Thoracic Society recommend
BCG for infants and children intimately exposed to TB that is
"persistently untreated, ineffectively treated, or resistant to
isoniazid and rifampin and who cannot be removed from the source of
exposure or placed on long-term preventive therapy." The AAP and ACIP also
recommend it for children in groups with a rate of new TB infections
greater than 1% annually "and for whom the usual surveillance and
treatment programs have failed or are not feasible." (_AHFS Drug
Information_) ACIP also recommends vaccination for children who
are continually exposed to a patient who is infected with a strain
of TB which is resistant to isoniazid and rifampin (MMWR, April 26,
1996). It is recommended for travel only for people who will
be in a high risk environment for a long time without access to TB skin
testing. It is currently not recommended for health care workers (skin
testing and isoniazid is considered to be enough), but this recommendation
is periodically reevaluated because of the incidence of TB in AIDS
patients.
BCG also has some use against certain tumors (in particular, bladder
cancer).
Hypersensitivity to the vaccine, positive TB skin test, recent smallpox
vaccination, burn patients, various immune deficiencies or
immunosuppressive therapy (see _AHFS Drug Information_ for a list).
In case of eczema or other skin disease, give it in a different area
of the skin. Although no harmful effects to the fetus are associated
wtih BCG vaccination, its use is not recommended during pregnancy.
Vaccine components capable of causing adverse reactions: Triton WR 1339
(Travel Medicine Advisor).
Q3j.8 What are some other methods of controlling tuberculosis?
Tuberculin skin screening and use of drugs such as isoniazid.
Pasteurization of milk and testing of cows for tuberculosis
are also useful.
===============================================================================
[Hepatitis A: The following was taken from an article in JAMA
(March 22/29, l995--Vol 273 (12) 906-907) and information from the
*draft* hepatitis A vaccine recommendation which was, as of April
l995, under consideration by the ACIP It has since been updated
based on the ACIP and AAP recommendations as of December 1996, the
CDC Vaccine Information Statement on hepatitis A as of 8/25/98,
and articles at Medscape. This section last updated September 19,
1999.]
Q3k.1 What is hepatitis A and what are the risks of the disease?
There are several forms of hepatitis (infection of the liver) which
cause jaundice, nausea and weakness. Hepatitis A is caused by
infection with hepatitis A virus (HAV) which is acquired primarily
through a fecal-oral route, most often from person to person. It
can also occur via ingestion of contaminated food or water. The
illness consists of mild flu-like symptoms or severe nausea lasting
for weeks. Hepatitis A does not become chronic and is rarely
fatal. In children under 6, most cases (>70%) of hepatitis A
are asymptomatic, and if illness occurs, it is usually not accompanied
by jaundice. Among older children and adults, the illness is
usually symptomatic, and jaundice occurs in >70% of cases. Symptoms
usually last for <2 months, but 10-15% of people infected have
illness or relapses for up to 6 months. 11-22% of people who have
hepatitis A are hospitalized, and hepatitis A is responsible for
an estimated 100 deaths a year (these numbers from the ACIP
recommendation on hepatitis A - the AAP recommendation gives similar,
but not identical, numbers).
Hepatitis A should not be confused with hepatitis B, which is less
contagious but more serious. Hepatitis B becomes chronic in 5-10%
of those infected. Complications include hepatic necrosis,
cirrhosis of the liver, chronic active hepatitis, and
hepatocellular carcinoma.
Some sources of general information on hepatitis can be found in the
hepatitis B section of this FAQ.
Q3k.2 How common is hepatitis A?
During the past several decades, the incidence of hepatitis A in
the U.S. has been cyclic, with nationwide epidemics occurring every
10-15 years; the last occurred in l989. Between epidemics,
hepatitis A continues to occur at relatively high levels.
Nationally, CDC estimates that around 75,000 cases occur annually.
Children play an important role in HAV transmission, with highest
rates among those aged 5-14 years. Rates are substantially higher,
in the Western US states than in other US regions. The highest
rates of hepatitis A are among children 5-14 years of age. In the
US, 33% of the population has evidence of prior hepatitis A
infection, as determined by a survey conducted from 1988-1991 (reported
in the ACIP recommendation for hepatitis A). Prevalence is
generally higher among Native Americans and Mexican Americans.
Hepatitis A is the most common vaccine preventable illness among
travelers. It can be avoided by avoiding contaminated food and drink, but
many travelers succumb to temptation, assume food at hotels is safe, buy
from street vendors, etc. Incidence is 1.6 per 1000 person-months of
travel among travelers to developing countries (including those who stay
in luxury hotels), and 20 per 1000 among backpackers and others who eat
and drink in poor hygienic conditions. Incidence is 0.05 to 0.10 per 1000
person-months of travel in Southern Europe. (JAMA Sept 21, 1994 p. 885)
Q3k.3 Who is at risk for acquiring hepatitis A?
International travelers and individuals residing in hepatitis A
endemic areas are at risk for acquiring disease. Other risk groups
include homosexual men, injecting drug users, hemophilic patients,
veterinary workers and certain research occupations working with
infected animals (particularly people working with non-human primates).
Workers at day care centers, institutions for the developmentally
disabled, food service establishments and healthcare settings are
also at some increased risk.
Q3k.4 Is there a vaccine to protect against hepatitis A?
Yes, the FDA licensed the hepatitis A vaccine for use in persons 2
years of age and older on February 22, l995. An ACIP recommendation
was published in the MMWR for December 27, 1996. The American Academy
of Pediatrics also published a policy statement in December 1996. The
vaccine has been in use in Europe since 1992.
Q3k.5 How is it to be administered?
According to the labeling, the vaccine is given in a two-dose
schedule to adults 18 years of age and older, the second dose being
given 6-12 months after the first. Children and adolescents 2-18
years of age are given 3 doses. The second dose is given 1 month
after the first and the third dose 6-12 months later. It is
administered by intramuscular injection in the deltoid (upper arm),
and can be given with other vaccines without loss of
immunogenicity.
Q3k.6 How effective is the vaccine?
A single dose of the vaccine induced antibodies in 88% to 96%
of subjects by two weeks and in 97% to 100% by one month.
Completion of the full vaccine schedule is recommended to ensure
high antibody levels and long-term protection. Efficacy trials
in children and adolescents show it is 94% (or more) effective
against endemic hepatitis A virus.
According to the AAP recommendation for hepatitis A, on December,
1996: "Clinical studies suggested a possible herd-immunity effect
if more than 80% of the estimated susceptible individuals were
vaccinated. A single dose of Havrix in Alaskan native villages
with endemic HAV disease resulted in a dramatic decrease
in cases within 8 weeks of vaccination. A similar abrupt
decrease in HAV cases was observed after two doses of vaccine
in two Slovak Republic villages experiencing a large community
outbreak. In the Vaqta trial in New York State, no cases
of clinical and confirmed hepatitis A occurred in vaccine groups
more than 21 days after the first dose, and the calculated
protective efficacy was 100%. "
Q3k.7 How long does immunity last?
Firm data on long-term protection are limited because the vaccine
was under investigation for only 4 years before being approved in
1995. Estimates of antibody persistence derived from kinetic models
of antibody decline suggest that the protective levels of anti-HAV
could persist for at least 20 years.
Q3k.8 What are some of the risks of the vaccine?
Information on adverse events comes from prelicensure clinical
studies worldwide and reports following vaccine licensure in Europe,
the US, and Asia. No serious adverse events have been attributed to
the vaccine. Side effects include soreness and redness at the
injection site, headache and fatigue. In very rare cases, there
is a severe allergic reaction within a few minutes to a few hours
of the shot.
Q3k.9 When is hepatitis A vaccine contraindicated?
The vaccine should not be administered to persons with a history of
hypersensitivity reactions to any of the vaccine components,
including alum or the preservative (2-phenoxyethanol). Because it
is inactivated, no special precautions need be taken when
vaccinating immunocompromised individuals. The inactivation also
means that they theoretical risk to a fetus is low, but there are
no data to determine the safety of the vaccine during pregnancy.
People mildly ill at the time of vaccination may get the vaccine,
but people moderately to severely ill should wait until they
recover.
Q3k.10 What groups at risk are be included in a recommendation to receive
hepatitis A vaccination?
ACIP recommends the vaccine for:
1. Persons 2 years of age or older traveling or working in countries with
high or intermediate endemicity of infection. The vaccine series should
be started at least one month before travelling.
2. Persons living in communities with high rates of HAV infection; for
example, American Indian, Alaska Native, Pacific Islander, and some
religious communities.
3. Men who have sex with men.
4. People who use street drugs (injected or non-injected).
5. People who work with hepatitis A infected primates or with hepatitis
A in a research setting should be vaccinated. No other groups have
been shown to be at increased risk for hepatitis A due to occupational
exposure.
6. Persons with chronic liver disease.
7. Persons who use clotting factor concentrates.
8. Since people who work as food handlers can contract hepatitis A and
pass the disease to others, they may be vaccinated in areas where state
and local health authorities determine such vaccination to be cost
effective.
The AAP recommends the vaccine for the first six of the groups listed
above, and suggests consideration of potential use for child care
center staff and attendees, custodial care institutions, hospital
personnel, food handlers, and people with hemophilia.
In 1999, ACIP recommended hepatitis A vaccine for all children aged
2 years and older in the 11 Western states where incidence is especially
high (at least 20 cases per 100,000 people, twice the national average).
These states are: Arizona, Alaska, California, Idaho, Nevada, New Mexico,
Oklahoma, Oregon, South Dakota, Utah and Washington.
Any healthy individual 2 years of older may receive hepatitis A
vaccine at the discretion of the physician and patient or parent.
Q3k.11 Is it possible that hepatitis A vaccine (like hepatitis B vaccine)
might eventually be recommended for routine administration to
children and adults?
Those in public health say that control of hepatitis A infection
will be facilitated by the development of vaccines that combine
hepatitis A with other routine childhood immunizations. The CDC's
draft statement notes the important role of children in hepatitis
A transmission, and that "it is likely that routine childhood
vaccination will be the only way to significantly decrease
hepatitis A rates in the U.S."
===============================================================================
Q3l.1 What is rotavirus, and what are the risks of the disease?
Rotavirus is one of the major causes of gastroenteritis among
infants and small children in most countries. Symptoms are fever,
vomiting, diarrhea, and dehydration, with vomiting and dehydration
more common than with other diarrheas. The illness
normally lasts 3-9 days, and becomes chronic only in
immunodeficient children.
Group A rotavirus is a major cause of infant mortality in many
parts of the world. 873,000 infants and children under
5 die per year of rotavirus in developing countries.
Non-group A rotavirus is less frequent, and is epidemic only
in China. In tropical climates, rotavirus infection occurs
year round, while in temperate climates it is seasonal.
Rotavirus can survive for hours on human hands and for days
on inanimate surfaces, and resists common disinfectants.
Rehydration therapy makes death infrequent in developed countries.
On the other hand, it is one of the most common causes of
hospitalization among infants during the winter months.
Cecil Textbook of Medicine estimates that it is responsible
for 35-52% of the cases acute diarrheal illness needing
hospitalization in infants and young children, in US.
Q3l.2 How common is rotavirus?
The AAP Committee on Infections Diseases estimates that
rotavirus is responsible for 3 million cases of diarrhea,
50,000 hospitalizations, and 20 to 40 deaths each year in the
United States.
Q3l.3 What is the current status of the rotavirus vaccine?
On October 15, 1999, Wyeth Lederle Vaccines announced that it
has withdrawn its RotaShield vaccine from the market and
has requested the immediate return of all doses of the
vaccine. The company's press release can be accessed at
the web address below.
http://www.ahp.com/releases/wa_101599.htm
A brief history of the release and withdrawal of this vaccine follows.
After years of research (animal studies beginning in 1983, and
human trials in 1987) into an effective rotavirus vaccine
(with a couple of candidates being rejected), a live, oral,
tetravalent rotavirus vaccine was approved by the FDA on
August, 1998. This vaccine is composes of one rhesus monkey
virus, and three genetically engineered combinations of
rhesus monkey and human rotavirus. In the December, 1998 issue
of Pediatrics, the AAP Committee on Infections Diseases
recommended that the vaccine be added to the standard
vaccination schedule, with shots being given at 2, 4, and
6 months, with the understanding that it might take time
to incorporate the new vaccine into the schedule.
On July 18, 1999, US health officials recommended postponement of
rotavirus vaccine. Shipments have temporarily been suspended.
The company which makes the vaccine is working with the CDC to
investigate reports of bowel obstruction among infants who
received the vaccine. An additional reason for postponement
was the fact that the rotavirus season, in the US, occurs during
the winter, allowing several months for investigation of these
adverse reactions, before a decision needed to be made about
whether the vaccine should be used prior to this year's rotavirus
season. Results of a case-control study were expected to be
available by October, 1999. Additional studies could
continue into next year. Further
information from the CDC about rotavirus vaccine and intussusception
can be found at http://www.cdc.gov/nip/Q&A/genqa/Rotavirus.htm
and at http://www.cdc.gov/nip/news/rotavirus.htm.
Q3l.4 How effective is the rotavirus vaccine?
Although the rotavirus vaccine has been withdrawn as of October, 1999,
I am retaining the answer to this question, in case it should be later
reintroduced in some form.
The rotavirus vaccine doesn't confer full immunity, but protects
against severe illness (this is also the case with natural
immunity from prior rotavirus infections). Trials by the
manufacturer, used for FDA approval, showed the following
results:
Trial 1: None of the infants receiving the vaccine got dehydrated,
compared to 3% in the placebo group. 11% fewer in vaccine group
needed a visit to the doctor. 88% showed elevated IgA titers.
Trial 2: 9% of infants in placebo group saw a doctor for diarrhea
and vomiting, compared with 2% in vaccine group. None in the
vaccine group needed hospitalization.
Both trials were by the manufacturer, and not published
in the medical literature at the time of approval.
A third trial, in Finland, showed similar results.
Q3l.5 Is the rotavirus vaccine effective for breastfeeding infants?
Although the rotavirus vaccine has been withdrawn as of October, 1999,
I am retaining the answer to this question, in case it should be later
reintroduced in some form.
For infants receiving the full three doses, breastfeeding
infants show the same level of immunity as formula-fed
infants. For infants receiving only one dose, immunity
may be less among breastfed infants.
Q3l.6 How long does the rotavirus vaccine last?
Although the rotavirus vaccine has been withdrawn as of October, 1999,
I am retaining the answer to this question, in case it should be later
reintroduced in some form.
Efficacy persisted for two years in US and Finnish trials.
Since followup has only been done for two years, it is not
known whether efficacy persists beyond that time.
Q3l.7 What is intussusception?
Intussusception is a bowel obstruction in which one segment
of the bowel becomes enfolded within another segment.
Q3l.8 What is the relationship between the rotavirus vaccine and
intussusception?
15 cases of intussusception, possibly associated with
administration of the rotavirus vaccine, have been reported
to VAERS. These cases were analyzed in "Intussusception
Among Recipients of Rotavirus Vaccine -- United States,
1998-1999," MMWR 48(27);577-581, 1999, Centers for Disease
Control.
VAERS reports of intussusception were reviewed, and parents
or guardians or health-care providers contacted by phone for
clinical and demographic data. Data on vaccine distribution
was also obtained from the manufacturer.
13 of the 15 developed intussusception after the first dose,
and 12 of the 15 developed symptoms within a week of receiving
any dose. Intussusception confirmed radiologically in all.
8 needed surgical reduction. All recovered. 14 were spontaneous
reports, and one was obtained through active postlicensure
surveillance. According to the report, "The manufacturer had
distributed approximately 1.8 million doses of RRV-TV as of
June 1, 1999, and estimated that 1.5 million doses (83%) had
been administered. Given this information, 14-16
intussusception cases among infants would be expected by chance
alone during the week following receipt of any dose of RRV-TV.
As part of a preliminary analysis of postlicensure adverse
events, cases of intussusception during December 1, 1998-June
10, 1999 were identified in Northern California and Minnesota,
and the rate in vaccinated and unvaccinated children was
compared. Vaccinated children showed a statistically higher
incidence of intussusception.
A further announcement by the FDA, made on September 14, 1999,
reported that the number of cases of intussusception that may
be related to the rotavirus vaccine (15 as of July 7), is
now up to 99, including two deaths. The FDA's Dr. Kathryn
Carbone, one of the initial reviewers of the rotavirus data,
reported to a gathering of the FDA's Vaccines and Related
Biological Products Advisory Committee that all these cases
are still under investigation, and it is not clear yet
whether the two deaths or the other cases were caused by the
vaccine.
Further study is being done.
Q3l.9 Why was a connection between the rotavirus vaccine and
intussusception not observed prior to FDA approval of
the vaccine?
Approval by the FDA only requires trials on about 5,000-10,000
subjects. Rare reactions to a new drug or vaccine will therefore
be unknown at the time of FDA approval.
Q3l.10 What other reactions have been reported following the
rotavirus vaccine?
Although the rotavirus vaccine has been withdrawn as of October, 1999,
I am retaining the answer to this question, in case it should be later
reintroduced in some form.
Mild, fever, for usually less than 24 hours. Fever after the
first dose is more common in older children, for which reason
it is recommended that the vaccination series be begun by the
time a baby is six months old. All doses should be given by
12 months, because data regarding the safety and efficacy of
vaccine administration to older children are not available.
Irritability, decreased appetite, and decreased activity,
were reported more often than with the placebo for five days.
Diarrhea was not reported more often than with the placebo.
Q3l.11 Can the rotavirus vaccine be effectively used in developing
countries?
Price may be the major barrier, as it is one of the more
expensive vaccines (and not likely to get cheaper if any modified
version is reintroduced later).
Q3l.12 When is the rotavirus vaccine contraindicated?
Although the rotavirus vaccine has been withdrawn as of October, 1999,
I am retaining the answer to this question, in case it should be later
reintroduced in some form.
The rotavirus vaccine should not be given in case of:
Infants with hypersensitivity to aminoglycoside antibiotics,
amphotericin B, or monosodium glutamate that are components of
the vaccine, or an anaphylactic reaction to a previous dose of
the rotavirus vaccine.
Until further data are available, this live-attenuated
vaccine should not be given to children who are immunosuppressed
or immunodeficient. Babies of women who are HIV-infected
should not get the vaccine unless these babies have tested
as HIV-negative at the age of two months or older.
The rotavirus vaccine should be postponed in case of:
Acute vomiting and diarrhea (efficacy is uncertain in this case).
Moderate or severe fever.
The rotavirus vaccine may be given in case of:
Breastfeeding, premature birth, and low grade fever.
The vaccine can be given at same time as DTaP or DTP, HiB,
hepatitis B, or IPV/OPV, and there is no need to adjust
the timing for antibody-containing blood products.
Infants living with people known or suspected to be
immunocompromised may be immunized.
===============================================================================
Q3m.1 What other vaccines are available and when are they given?
Other vaccines available include vaccines for cholera, Japanese
encephalitis, typhoid, yellow fever, rabies, plague, Lyme disease,
and anthrax. _Travel Medicine Advisor_ also mentions a vaccine
for typhus, but, according to the 1996-1997 edition of the CDC
Yellow Book (CDC Health Information for International Travel),
"production of this vaccine has been discontinued in the US and
there are no plans for commercial production of a new vaccine."
Since other countries may offer typhus vaccination (though, to
the best of my knowledge, it is not required for travel to any
country), I am drawing information for this vaccine from a German
web site. Immune globulins are also available for a variety of
diseases.
For more information on these other vaccines, check the _American
Hospital Formulary Service Drug Information_ (a better source than
the PDR in this case) and _Health Information for Travelers_,
which is put out by the CDC every year (vaccination and booster schedules
for all of these vaccines can be found there, as can information on where
these diseases are common and what vaccination requirements various
countries have for entrance). The latter can be purchased from the
Superintendent of Documents, U.S. Government Printing Office, Washington,
D.C. 20402, and most local health departments have a copy which can be
consulted, sometimes by telephone. It can also be found in some public
libraries. The CDC also has a Worldwide Web site which can be accessed
for travel information: http://www.cdc.gov/. The International
Association for Medical Assistance to Travellers (IAMAT), which has
affiliated institutions in over 115 countries, puts out a _World
Immunization Chart_. The address of the U.S. affiliate is IAMAT,
736 Center Street, Lewiston, N.Y. 14092. The World Health Organization
produces a publication on international travel; it is called
_INTERNATIONAL TRAVEL AND HEALTH: Vaccination Requirements and
Health Advice_, and copies may be ordered from WHO Distribution and Sales,
CH-1211, Geneva 27, telephone (41 22) 791 2476; fax (41 22) 788 0401.
The price is 15 Swiss Francs; in developing countries: 10.50 Swiss
Francs. Further information about rabies can be found in books on
mountaineering and spelunking (the one I consulted is _Medicine for
Mountaineering_, by James A. Wilkerson, M.D.). Hepatitis B, hepatitis A,
and meningococcus vaccines are given for travel, so people interested in
travel vaccinations may want to check the sections of this FAQ dealing
with those vaccines.
Anthrax vaccine, in the US, is mainly used by the military as a
protection against biological warfare; small quantities are also
made available to people with an occupational exposure, such
as veterinarians and lab workers. Since vaccines given by the
military to soldiers are outside the scope of a FAQ primarily
concerned with vaccines which might be given to children, I will not
be discussing the anthrax vaccine further.
Cholera is an intestinal infection spread by contaminated food and
water. Cholera vaccination is about 25-50% effective in reducing clinical
illness for 3-6 months after vaccination (with the greatest protection
during the first two months). (_Health Information for Travellers_ gives
the effectiveness as 50%, and AHFS Drug Information gives it as 25-50%.)
Boosters are every six months for travelers who will be staying for a
long time in cholera-endemic areas. Serious reactions are rare.
Since the effectiveness is so low, neither the CDC nor the WHO actually
recommends the vaccine, but some countries require it. According to
AHFS Drug Information, "_Cholera vaccine does not prevent transmission
of infection_, and should not be used to manage contacts of imported
cholera cases or to control the spread of infection."
Vaccine components capable of causing adverse reactions: bacterial
components (Travel Medicine Advisor). The vaccine should not be given
to children under 6 months.
Japanese encephalitis B vaccine, licensed in 1993, is given to travelers
"who expect to go beyond the usual tourist routes or to spend extended
time in rural areas in disease endemic regions" (Harrison's) Its
efficacy is estimated at 80-90%. Anaphylactic and severe delayed
allergic reactions are common, so people who receive this vaccine should
be observed for ten days.
Lyme disease vaccine, licensed on December 21, 1998, is licensed (as
of September, 1999) only for people 15 years or older, though that
age limit may soon be eliminated. It is recommended for adults and
older teens who spend lots of time outdoors in Lyme-endemic areas.
You should still protect yourself against ticks if using the vaccine,
both because the vaccine isn't 100 per cent effective and because ticks
also carry other diseases. In a randomized, double-blind, multicenter
trial involving 10,936 people living in the northeastern and upper
north central United States, the vaccine efficacy at preventing
Lyme disease was 50% (MMWR, January 22, 1999 / 48(02);35-36,43).
The duration of immunity is unknown. Side effects included local
reactions, transient myalgia or arthralgia, influenza-like illness,
fever, and chills.
It is unlikely that your child will ever need a plague vaccination. The
disease is found among rural rodents in some areas, including the Western
third of the US, but urban outbreaks are now rare. Vaccination is only
recommended for people at increased risk due to research or field
activities in epizootic areas. An alternative for people at increased
risk is tetracycline prophylaxis. _AHFS Drug Information_ gives the
vaccine's effectiveness as 90% for 6-12 months. Other measures for
avoiding plague in epizootic areas are getting rid of wild rodent food
and shelter, defleaing dogs and cats weekly, avoiding sick or dead
rodents, and routine bacteriologic precautions in labs.
Vaccine components capable of causing adverse reactions: phenol, beef
protein, soya, casein (Travel Medicine Advisor).
Rabies, an almost universally fatal disease transmitted by saliva and
brain tissue of infected animals, is rare in the US but more common in
some countries where pet vaccination is not common. Dogs are the main
reservoir in developing countries, but all animal bites should be evaluated.
The most common animal vectors in the US are carnivorous small animals
(such as skunks, racoons, foxes, coyotes, and bobcats) and bats. There
has been a recent increase in racoon rabies in the mid-Atlantic and
northeastern states of the US (MMWR 29 Apr 1994), and programs to institute
oral rabies vaccination of racoons, foxes and coyotes have been initiated
in some state (similar programs have been used to control fox rabies in
Canada and Europe). More than 50% of rabies cases in the US come from
exposure to rabid dogs outside the US. The disease is most commonly spread
by animal bites, but can also be caught through non-bute exposure, including
contact between infected saliva or brain tissue and pre-existing cuts,
scratches, open wounds, or mucuous membranes. There are also cases of
aerosolized transmission in medical laboratories and caves inhabited by
rabid bats, and transmission through cornea transplants from people who had
died of undiagnosed (before the transplant) cases of rabies. The chance of
infection is more likely in case of bite or non-bite exposure to the head,
neck, face, shoulders, or hands, than with similar exposure to the trunk
or legs.
In case of exposure to rabies, the wound should be immediately and
thoroughly cleaned with soap and water. "Although not included in the
ACIP recommendations, some clinicians also rinse the wound thoroughly
with water or 0.9% sodium chloride solution and then cleanse with a
topical antiseptic (e.g. povidone-iodine)." (AHFS Drug Information 1992)
It is also important to promptly vaccinate anyone exposed to rabies
(and give rabies immune globulin if the person has not been previously
vaccinated), as the disease is, for all practical purposes, always
fatal once rabies symptoms begin to show up. (A few people have recently
survived after symptoms appeared, but they all had serious brain damage.)
Pre-exposure vaccination is given to people who live in or visit rabies
endemic areas and to people whose professions or activities put them at
extra risk, such as lab workers, veterinarians, and spelunkers. The
highest travel risk is where dog rabies is still endemic.
There is some drug interference between chloroquine (an anti-malarial
drug) and rabies vaccine, but intramuscular injection can take care of
the problem. Need for boosters depends on risk category, and ranges from
regular tests of antibody levels every six months, with vaccination when
they drop, for rabies lab workers, to no pre-exposure vaccination for
most people. Post-exposure, unvaccinated people get rabies immune
globulin and rabies vaccine, while previously vaccinated people get
rabies vaccine alone, in a smaller amount. Adverse effects include local
reactions (30-74% of vaccinees) and mild systemic reactions (e.g. headache,
nausea, 5-40% of vaccinees). About 6% of vaccinees have a reaction
characterized by urticaria, pruritis, and malaise. Rarely, anaphylactic
shock may occur. Because rabies is so deadly, pregnancy is *not* a
contraindication to postexposure vaccination.
Vaccine components capable of causing adverse reactions: neomycin, phenol
red, thimerosal (Travel Medicine Advisor).
The following posting from sci.med, by Achim Lohse, provides further
information about rabies vaccine (the side effect under discussion is
anaphylactic shock):
Vaccine components capable of causing adverse reactions: polymyxin B,
streptomycin, chlortetracycline, neomycin, phenol, brilliant green
dye, glycerin (Travel Medicine Advisor).
Typhoid is spread by contaminated food and water. The vaccine protects
70-90% of recipients. There are two forms of the vaccine: oral (live),
and parenteral (killed). The oral vaccine shouldn't be given to
immune-compromised people. Otherwise, there are few adverse reactions,
mostly local discomfort and sometimes fever and malaise. Boosters are
every three years for parenteral and five years for oral vaccine.
Vaccine components capable of causing adverse reactions: phenol,
bacterial components (Travel Medicine Advisor).
The following posting from sci.med gives further information on
typhoid vaccine:
Yellow fever is a viral infection which is spread by mosquitos. Yellow
fever vaccine is a live vaccine which can be given only at certain
vaccination centers. Many countries require this vaccination for entry.
A booster is needed every ten years. Contraindications include egg
allergy and immune deficiency. Reactions are mostly mild.
Vaccine components capable of causing adverse reactions: chick embryo
components (Travel Medicine Advisor).
Travelers may also want to take anti-malarial drugs, bring insect
repellant containing N,N diethylmethylbenzamide, and avoid unboiled
water, raw vegetables, fruit they haven't peeled themselves, undercooked
fish and shellfish, and food kept at room temperature. Other sources of
travel health information are _Fielding's Travelers' Medical Companion_
and the US State Department Citizen's Emergency Center, which provides
information on a variety of foreign travel risks 24 hours a day at
202-647-5225. CDC Travelers' Health Section, 404-332-4559, and
Immunization Alert, 203-487-0611, have up-to-date information on
vaccinations for international travel.
===============================================================================
[This section most recently updated on September 18, 1999. References
include the Report of the Technical Review Group Meeting, 7-8 June 1998
WHO Global Program for Vaccines and Immunization Vaccine Research and
Development (http://www.who.org/gpv-documents/DocsPDF/www9845.pdf),
a New England Journal of Medicine editorial on malaria vaccine
development at http://www.nejm.org/content/1997/0336/0002/0128.asp,
reports on AIDS vaccine research at http://www.iapac.org/ and
http://www.nih.gov/news/pr/may98/od-15a.htm, an Intellihealth report
on vaccine news for 1999 (http://www.intelihealth.com/IH/ihtIH?t=18784&p=~br,IHW|~st,408|~r,WSIHW000|~b,*|), Lon Morgan's Web site on
vaccine developments:
http://fp1.cyberhighway.net/~lmorgan/developments/vaccine_development.htm,
and National Institute of Health information on clinical trials at
http://www.niaid.nih.gov/.]
Q3n.1 What vaccines are currently under development?
New vaccines under development include vaccines for HIV (vaccines are
being tested both to improve the immune response in those already infected
and to resist infection), respiratory syncytial virus
(Rathone), malaria, leprosy, gum disease, herpes, shigella,
dengue, cervical cancer, type I diabetes, and other
illnesses, as well as an intranasal flu vaccine, new versions of
the pneumococcal, meningococcal, and TB vaccines. Harrison's
Internal Medicine has a list of vaccines in human trial, and a list
of those toward which priority efforts are being targetted.
As of May, 1998, the National Institutes of Health had evaluated
23 vaccine candidates and 10 adjuvants (substances that
might enhance the effect of a vaccine) in 49 Phase I and
Phase II clinical trials to determine the safety of the
vaccine candidates and their effect on the human immune system.
These studies have been conducted with 2,900 volunteers. Despite
all these vaccine candidates, the variation of retroviruses and the
virus transmission directly from cell to cell by fusion pose significant
obstacles. It's anyone's guess when (and if) an AIDS vaccine will
be ready. Two articles which discuss AIDS vaccine development are
"Vaccine Against AIDS?" in the British medical journal Lancet
((02/26/94) Vol. 343, No. 8896, P. 493) and "AIDS Vaccine: Shooting
Blanks or Loaded for Bear?" in Men's Fitness ((03/94) Vol. 10, No.
3, P. 118). Information about efforts to produce an AIDS vaccine
is sometimes posted in sci.med.aids, and references, updates, and
current information is available by gophering to odie.niaid.nih.gov.
If you have gopher, gopher odie.niaid.nih.gov will get you there.
The AIDS FAQ (available from the pub/usenet/sci.med.aids directory
of rtfm.mit.edu) describes some other Internet resources with
information about AIDS.
When I wrote this section in 1994, I had, "The malaria vaccine has
shown positive results in Phase I/II trials, which were reported on
February 18, 1994 issue in the British medical journal _Vaccine_
(volume 12 no. 4, pp 328-336; 1994). (A report on an earlier trial
can be found in the medical journal Lancet, volume 341, pp 705-710;
l993). More details can also be found in a WHO press release kept on
gopher.who.ch. The first results of Phase III trials are expected to be
available in October 1994." Unfortunately, the years since then
have not seen as much progress toward a malaria vaccine as was hoped.
It is known to be possible to induce immunity to malaria, as letting
volunteers be bit by irradiated mosquitos has done so. But translating
that into an effective vaccine has proved tricky. An editorial in
The New England Journal of Medicine -- January 9, 1997 -- Vol.
336, No. 2 reported that, though one vaccine has shown efficacy,
recent trials in malaria endemic areas couldn't confirm that efficacy.
An improved subunit vaccine reported in the same issue of NEJM, but
needs to be tested in malaria endemic areas. WHO has malaria vaccine
as a high priority, and aims to have an effective and affordable
vaccine within the next decade.
Respiratory syncytial virus (RSV) is a major respiratory pathogen among
infants and young children which results in an "estimated 90,000
hospitalizations among infants in the US every winter" (Williams, 1997).
Trials have indicated that the vaccine is safe and immunogenic
(produces antibodies), but there are mixed results so far on efficacy.
Shigella is one of the leading causes of diarrhoeal illnesses. A shigella
vaccine is moving toward clinical trials soon.
The vaccine for periodontitis (gum disease) has shown some positive
results in macaque monkeys (less bacterially induced bone loss in the
vaccinated monkeys), indicating that a human periodontitis vaccine is
feasiable. Full-fledged clinical trials, however, may be a decade away.
Q3n.2 What other research is being done to improve vaccines?
Research is being done to improve existing vaccines (such as the research
which resulted in the new acellular pertussis vaccine). This includes
efforts to decrease the number of visits, the number of doses, and the
number of injections, to move immunization as early in life as possible
(including research into the value of giving vaccines to pregnant women to
provide protection to infants very early in life), to decrease adverse
effects, to increase protection, and to increase thermal stability. One
area being explored is whether it is possible to combine more vaccines in
a single shot. Micro-encapsulation is an attempt to encase vaccines in
microcapsules which will be released over time, mimicking repeated
injections. Trans-disease vaccinology is an attempt, by genetic
engineering, to create vaccines which protect against more than one
disease. Efforts are also under way to produce a heat-resistant polio
vaccine. (Hartveldt) (There is also a United Press International article
from 3/25/94, included in the CDC AIDS Daily Summary for March 28, 1994,
which discusses the effort to make a vaccine which will be effective
against a variety of different viruses.)
A major vaccine safety problem is the widespread reuse of syringes in
developing countries, due to scarcity, resale value, and cultural
resistance to waste. In response to this problem, monodose, disposable
vaccines, and solid, non-injected vaccines are being looked at. Solid
vaccines would also eliminate the cost of keeping vaccines cold (a major
factor in vaccine delivery costs, and reduce the cost of wasted vaccines.
Other research on different vaccine delivery methods includes work on
an intranasal flu vaccine and on an aerosol measles vaccine.
===============================================================================
AAP recommendations (found at http://www.aap.org).
ACIP recommendations (found at http://www.cdc.gov/nip)
AMA Drug Evaluations Annual, 1993.
The American Medical Association Family Medical Guide. Random House, New
York. 1987.
The American Hospital Formulary Service Drug Information, 1992.
Published by the American Society of Hospital Pharmacists.
Boughton, Clement R. "Varicella-zoster vaccine." The Medical Journal of
Australia. Vol. 159. 4 October 1993.
California Morbidity, a Biweekly Report from the Division of Communicable
Disease Control, part of the State of California Health and Welfare
Agency. Issues from October 31, 1987, May 21, 1993, and November 19,
1993.
Catalana, Paul, MD. "The 'Other' Childhood Immunizations." Emergency
Medicine, October 15, 1992.
Center for Disease Control. _Health Information for International
Travel_, 1992.
Center for Disease Control Vaccine Information Statements (found at
http://www.cdc.gov/nip).
Clements, C. John, Strassburg, Marc, Cutts, Felicity T. and Torel, Carol.
"The epidemiology of measles." In _World Health Statistics Quarterly, Vol
45, No 2/3, 1992.
FDA. "Advisory Committee Discusses Chickenpox Vaccine." January 28, 1994.
(Pulled off of fdabbs.fda.gov. Connect with login bbs to find this and
other FDA information.)
Fettner, Ann Giuici. _The Science of Viruses._ Quill. William Morrow, New
York, 1990.
Galazka, Artur. "Control of Pertussis in the World." In _World Health
Statistics Quarterly_, Vol 45, No 2/3, 1992.
Gershon, Anna A. "Varicella - Immunization Practices in Children."
Hospital Practice. Sept. 15, 1990.
Ghendon, Y. "Influenza - its impact and control." In _World Health
Statistics Quarterly, Vol 45, No 2/3, 1992.
Harrison's Principles of Internal Medicine, Eleventh Edition. McGraw
Hill Book Company, 1987.
Hartveldt, Frank. "The Children's Vaccine Initiative." World Health 46th
year, No. 2, March-April 1993.
Historical Statistics of the United States, Colonial Times to 1970.
Bicentennial Edition. US Department of Commerce, Bureau of the Census.
Hull, Harry F. and Ward, Nicholas A. "Progress towards the global
eradication of poliomyelitis." In _World Health Statistics Quarterly, Vol
45, No 2/3, 1992.
Journal Watch, 9-1-93. "Infant HBV Vaccination: Doubts Remain."
Kiple, Kenneth E., Editor. _The Cambridge World History of Human
Disease_.
The Lippincott Manual of Nursing Practice, Fourth Edition. 1986.
Mandell/Douglas/Bennett. Principles and Practice of Infectious Diseases,
Third Edition, 1990.
The Medical Letter on Drugs and Therapeutics, Vol. 34 (Issue 875), July
24, 1992.
The Merck Manual, Sixteenth Edition. Merck Research Laboratories, 1992.
Nossal, Sir Gustav. "Prospects for new vaccines." World Health 46th year,
No. 2, March-April 1993.
Onorato, Ida M., MD, Wassilak, Steven G. Md, Meade, Bruce, PhD. "Efficacy
of Whole-Cell Pertussis vaccine in Preschool Children in the United
States." JAMA, May 27, 1992, Vol. 267, No. 20.
Pantell, Robert H., MD, Fries, James F., MD, and Vickery, Donald M., MD.
_Taking Care of Your Child: A Parents' Guide to Medical Care._ Third
Edition.
The Physician's Desk Reference, 1993.
Rathone, Mobeen H., MD. "Childhood Immunizations: An Update." Infections
in Medicine, June 1992.
Ryan, Frank, M.D. _The Forgotten Plague: How the Battle Against
Tuberculosis Was Won - And Lost_. Little, Brown, and Company, 1993.
Shapiro, Eugene D., MD "Editorial: Pertussis Vaccines: Seeking a Better
Mousetrap." JAMA, May 27, 1992, Vol. 267, No. 20.
Smith, Alice Lorraine. Principles of Microbiology. The C. V. Mosby
company. St. Louis, Toronto, and London, 1992.
Statistical Abstracts of the United States, 1992.
Travel Medicine Advisor. May 1993.
Trollfors, B. and others. "A Placebo-Controlled Trial of a Pertussis-Toxoid
Vaccine." NEJM, Vol 333, Number 16, October 19, 1995.
University of California, Berkeley. _The Wellness Encyclopedia._ From the
editors of the UC Berkeley Wellness Letter. Houghton Mifflin Company,
Boston, 1991.
Viral Hepatitis Prevention Board. Safety of hepatitis B vaccination programmes.
http://esoc-www.uia.ac.be/esoc/VHPB/statement.html
Whitman, Cynthia, Belgharbi, Lahevari, Gasse, Francois, Torel, Carol,
Mattei, Vittoria, and Zoffman, Henrik. "Progress towards the global
elimination of poliomyelitis." In _World Health Statistics Quarterly, Vol
45, No 2/3, 1992.
WHO. The Work of WHO 1990-1991. Biennial Report of the Director General.
Wilkerson, James A., M.D. Medicine for Mountaineering, Third Edition.
The Mountaineers, Seattle, Washington, 1985.
Williams, Amelia L., Ph.D. News and Perspectives: New Vaccines for Childhood
Immunization. Drug Benefit Trends 9(3):10-11,15-22, 1997. (Found on Medscape.)
Wyngaarden/Smith/Bennett. Cecil Textbook of Medicine, 19th
edition, 1992.
Electronic resources consulted:
American Association of Pediatrics Web site.
http://www.aap.org
CDC AIDS DAILY SUMMARY (regularly posted on sci.med.aids)
CDC National Immunization Program Web site.
http://www.cdc.gov/nip/
Degos, Francoise. Immunisation contre le virus de l'hépatite B : bilan de
quinze années de vaccination.
http://www.john-libbey-eurotext.fr/articles/aB80DA9A7/index.htm
fdabbs.fda.gov (login using name "bbs") (more recently, http://www.fda.gov)
gopher.who.ch (gopher gopher.who.ch, also:
telnet gopher.who.ch login:gopher) (more recently, http://www.who.org)
HICNet Medical News Digest (available from LISTSERV@ASUACAD.BITNET;
regularly posted to sci.med)
Immunization Action Coalition Web site.
http://www.immunize.org
Journal Watch Summaries (regularly posted to sci.med by jwatch@world.std.com)
Le point sur la vaccination contre l'hépatite B
http://www.sante.gouv.fr/htm/pointsur/vaccins/effets_sec_hep_b.htm
Levy-Bruhl, Daniel et al. Comparaison entre les Risques de Premieres
Atteintes Demyelinisantes Centrales Aigues et les Benefices de la
Vaccination Contre L'Hepathite B.
http://www.rnsp-sante.fr/beh/1999/9909/index.html
Medscape
http://www.medscape.com
Also available on the net is the Morbidity and Mortality Weekly Report (MMWR).
It is available by Worldwide Web at:
http:/www.cdc.gov/; Go to publications and scientific data, then Morbidity
and Mortality Weekly Report, OR
by gopher at Duke University.
Morgan, Lon. Immunization, Vaccines, Vaccination in the Modern World
http://fp1.cyberhighway.net/~lmorgan/
Swiss Medical Weekly. http://www.smw.ch
A list of Internet and Bitnet Health Sciences resources, compiled by
Lee Hancock, can be ftped from the pub/nic directory of ftp.sura.net.
Section 1 of the misc.kids Childhood Vaccinations FAQ
Section 3g. Pneumococcal vaccine
[This section last updated September 18, 1999.]
From Nelson Textbook of Pediatrics, Behrman and Vaughn, eds.,14th edition,
1992:
------------------------------------------------------------------------
Pneumococcus (_Streptococcus pneumoniae_) is a normal inhabitant of the
upper respiratory tract (as many as 91% of children between 6 mo and 4
1/2 yr of age carry this bacterium at some time). Pneumococcus is the most
common cause of bacteremia (bacteria in the blood), bacterial pneumonia,
and bacterial otitis media (middle ear infections). Pneumococcus causes
25-30% of acute middle ear infections. It is also high on the list for
bacterial causes of meningitis.
------------------------------------------------------------------------
There has been recent evidence of antibiotic-resistant pneumococci (see
JAMA 1994; 271:1831; and MMWR 1994; 43:23; articles summarized in Journal
Watch, January 15, 1995 in the paper edition and February 7, 1995 in the
electronic edition).
Section 3h. Meningococcal vaccine
[This section last updated on September 18, 1999.]
Section 3i. Varicella (chicken pox) vaccine
*************************************************************************
[Contributed shortly before the vaccine was licensed.]
From J Thompson (jet14@columbia.edu):
I think it is almost guaranteed that adults will be able to get the
varicella vaccine. The only area where there is _no_ scientific controversy
over the wisdom of using this vaccine is in adults who are not immune.
Varicella in adults is a dangerous disease, sometimes leading to
hospitalization, and usually lasting two to three weeks.
*************************************************************************
ACIP recommends that people 13 years and older be assessed for varicella
immune status, and that those who are not immune be vaccinated. Priority
should be given to vaccinating those at highest risk for exposure and
for transmitting the disease. There is an antibody titre which can be
done on adults who are not sure whether they are immune to chicken pox.
*************************************************************************
From the April 1995 issue of Medical Sciences Bulletin, published by
Pharmaceutical Information Associates (pialtd@ix.netcom.com) and
available by Email subscription as MSB-L.
Use of Varivax is contraindicated for patients who are hypersensitive to any
component of the vaccine; those with a history of anaphylactoid reaction to
neomycin; those with active febrile infections, pregnancy, blood dyscrasias or
other malignancies, or primary or acquired immunodeficiency; and those
undergoing immunosuppressive therapy.
*************************************************************************
The July 12, 1996 ACIP recommendation lists, for the most part, the
same groups, but adds people who have experienced an anaphylactoid
reaction to gelatin, and people who have a family history of congenital
or hereditary immune deficiency in parents or siblings (unless their
own immune competence has been clinically substantiated or confirmed
by a laboratory). Pregnant women should not be vaccinated, as the
effect on the fetus is unknown.
Section 3j. BCG (tuberculosis) vaccine
[This section last updated on September 25, 1999, based on the ACIP
recommendation which was published in MMWR on April 26, 1996, and which
can be found at ftp://ftp.cdc.gov/pub/Publications/mmwr/rr/rr4504.pdf]
*************************************************************************
From J Thompson (jet14@columbia.edu):
The main strategy of TB control in the US is monitoring those at risk of
exposure to the disease for signs of TB infection. The main method used is
something called a "PPD" (which stands for purified protein derivative, i.e.
proteins purified from TB). A PPD is "placed" (injected subcutaneously) and
then the site of injection is monitored (usually at 48 hrs. after the
injection). Anyone who has mounted an immune response to a TB infection will
exhibit redness and swelling at the site of the PPD injection (the criterion
for calling a "true positive" PPD is that the inflammation must be at least
10 mm. wide). Also, this reaction must take place at a 1-2 day delay to be
diagnostic for TB infection (anything sooner is allergy, not a sign of
infection).
OK, what does all this have to do with BCG? Well, BCG, since it is very
similar to TB, can cause a positive PPD. Thus, widespread immunization with
BCG makes it more difficult to screen for TB, since the screening will pull
up many people who are not infected. The reaction due to BCG drops over
time, but it is still a problem, so that (combined with the low
effectiveness) has ruled out BCG in the US. Of course, now that
drug-resistant strains are becoming more common, opinions might change...
*************************************************************************
Q3j.6 When is the BCG vaccine recommended?
*************************************************************************
From J Thompson (jet14@columbia.edu):
The TB "shots" a poster on misc.kids referred to ("one misc.kids poster
reports that her city college system is now requiring TB shots") are most
likely PPD, not BCG. I believe that all schools receiving federal funding
(and I know that all schools I have attended) require either a PPD or the
(less accurate but easier to administer) "tine test" as part of the
pre-matriculation physical.
*************************************************************************
Q3j.7 When is the BCG vaccine contraindicated?
Section 3k. Hepatitis A
Section 3l Rotavirus vaccine
[This section last updated on October 23, 1999.]
Section 3m. Other vaccines which are available
[This section last updated September 17, 1999.]
----------------------------Original message----------------------------
...
In Canada (at least as of two years ago) there is only one rabies
vaccine availble, and the manufacturer supplies it only in one-millitre
vials, with strict instructions to use the entire vial for one injection
only. At $60 + per vial, the series of three costs over $180. I was
fortunate to have a physician who had worked among fur trappers up north,
and had some familiarity with the vaccine. He informed me that if
injected _intra_dermally, a dose of only 0.1 millilitre is enough.
I confirmed this with the local public health nurse, who showed me that it
had been standard public health procedure in British Columbia for five
years to use the 10% dose intradermally (10 trappers would arrange to
share the contents of a standard vial).
Later investigation via Medline showed that this particular vaccine
human diploid cell (HDCV) is not only the most expensive to produce,
but may also have a significantly higher rate of side-effects when
compared to the much less expensive purified chick embryo vaccine.
I had a taste of physician non-acceptance when my physician was away
after administering the first in the series of three shots. He assumed
any of the other five doctors in the rural practice could and would complete
the series. NOT! I was turned down flat by the two experienced doctors
on duty, and had to get my shot from the public health nurse.
Rabies antibodies (assuming the initial titres are adequate) are considered
to be reliably adequate for only three years, after which a booster is
required (and with the HDVC adverse reactions have most often been
experienced with the booster). The alternative is to get a Rabies titre
test, but I understand (anyone have figures?) that this is quite expensive,
and in Canada's health system, may simply not be available on demand in
some provinces (unless you can persuade a sympathetic public health official
of the need).
>However, since it's unusual for people to get rabies and the
>vaccine does work fine after exposure, it will probably not be
>part of the usual childhood vaccines.
>
>Mike K
As someone noted in a previous post, the urgency of treatment depends on
the proximity of the infection site to the brain. A report from a
researcher from pre-war Yugoslavia (Zagreb) indicated that there wolf
attacks resulting in bites to the face and neck have resulted in death,
due to inability to get the antibody titres high enough in time. One possible
strategy to improve this situation (suggested to me by Richard Passwater's
book "Selenium as Food and Medicine") is to take a large dose of selenium
concurrent with or within a few hours of vaccination. He reports that this
has greatly increased antibody titres with other vaccines.
Finally, aside from the risk of not being able to get to treatment in time
after clear exposure, there is the very real danger of unnoticed infection,
expecially in children, by having a cut finger or lip, etc. come in contact
with saliva from the tongue or coat of an infected animal. There is even
one reported instance of a spelunker dying after supposedly no other exposure
than inhaling saliva droplets from rabid bats. Since unvaccinated victims
can't be treated successfully once symptoms appear, pre-vaccination is the
only available protection for this last type of exposure.
Achim
lohseach@max.cc.uregina.ca achim.lohse@f45.n140.z1.fidonet.org
------------------------------------------------------------------------
From: Achim Lohse
Smallpox vaccine is no longer given, because smallpox has been eliminated
by vaccination. The virus is currently kept in labs in the US and
Russia, just in case it is needed at some point (there has been talk of
destroying the last samples, but the virus recently got a reprieve).
Since the elimination of smallpox is one of the major triumphs of
vaccination, which is mentioned in many medical texts which I consulted
as an argument in favor of vaccination, I'll also mention at this point
that smallpox mortality was 25-30%, that it infected 90% of the
population at risk, and that there were 10-15 million cases worldwide as
recently as 1967. The last natural case was reported in 1977, and the
last cases were reported in 1978, as a result of an escape of the virus
from a lab (the lab director committed suicide while under quarantine).
(Kiple) The only people who still need to be vaccinated for smallpox are
the people who work in the labs where the virus is kept.
------------------------------------------------------------------------
From: "Mark A. Shelly"
Typhus vaccine (not available in the US) is described by Andreas
Kaunzner's travel medicine Web site
(http://members.aol.com/reisemed/impfung/typhus.htm). According to
this site, there are two different typhus vaccines on the market
in Germany. One is a live oral vaccine, which is given in three
doses, and gives protection for about three years, if one stays
in a region where typhus is endemic; otherwise its immunity
lasts for about a year. The most common side effect, seen in
fewer than 1% of those receiving the vaccine, is stomach trouble.
General symptoms such as fever and chills can appear, and very
seldom a rash. The other is a killed vaccine, which may be given
to adults and children two years or older, and which provides
immunity for at least three years. Its side effects are described
as "typical side effects of vaccinations" (local reactions, fever,
and allergic reactions) appearing only seldom. Kabel 1 Online
has a chart of German travel vaccine recommendations
(http://www.kabel1.de/reise/1998/06/26/11/) which says that typhus
vaccine is given for trips of more than three months. The
CDC, on the other hand, recommends hygiene and, in areas where
tick typhus is endemic, tick removal and tick repellant; typhus
vaccine production has been discontinued in the US.
Section 3n. Vaccines under development
Section 4. References
Section 2 of the misc.kids Childhood Vaccinations FAQ
Section 4 of the misc.kids Childhood Vaccinations FAQ
Back to the Childhood Vaccinations page of the Children's Health page