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18楼
发表于 2006-10-25 17:51
分配给正义何在的部分,
已经发了邮件,为了避免失误,这里也贴出来.
需要在11月10日前完成.如有问题,请及时提出.
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Vaccine Safety
Hepatitis B vaccines have been demonstrated to be safe when
administered to infants, children, adolescents, and adults. Since
1982, an estimated >60 million adolescents and adults and
>40 million infants and children have been vaccinated in the
United States.
Vaccine Reactogenicity
The most frequently reported side effects among persons
receiving hepatitis B vaccine are pain at the injection site
(3%–29%) and fever >99.9° F (>37.7° C) (1%–6%)
(156,157). However, in placebo-controlled studies, these side
effects were reported no more frequently among persons
receiving hepatitis B vaccine than among persons receiving
placebo (87). Administration of hepatitis B vaccine soon after
birth has not been associated with an increased rate of elevated
temperatures or microbiologic evaluations for possible sepsis
in the first 21 days of life (158).
Adverse Events
A causal association has been established between receipt of
hepatitis B vaccine and anaphylaxis (159). On the basis of
data from the Vaccine Safety Datalink (VSD) project, the
estimated incidence of anaphylaxis among children and adolescents
who received hepatitis B vaccine is one case per 1.1
million vaccine doses distributed (95% confidence interval =
0.1–3.9) (160).
Early postlicensure surveillance of adverse events suggested
a possible association between Guillain-Barré syndrome and
receipt of the first dose of plasma-derived hepatitis B vaccine
among U.S. adults (161). However, in a subsequent analysis
of Guillain-Barré syndrome cases reported to CDC, FDA, and
vaccine manufacturers, among an estimated 2.5 million adults
who received >1 dose of recombinant hepatitis B vaccine during
1986–1990, the rate of Guillain-Barré syndrome
occurring after hepatitis B vaccination did not exceed the background
rate among unvaccinated persons (CDC, unpublished
data, 1992). A review by persons with clinical expertise concluded
that evidence was insufficient to reject or accept a causal
association between Guillain-Barré syndrome and hepatitis B
vaccination (159,162).
Multiple sclerosis (MS) has not been reported after hepatitis
B vaccination among children. However, one retrospective
case-control study (163,164) reported an association between
hepatitis B vaccine and MS among adults. Multiple other studies
(165–168) have demonstrated no association between hepatitis
B vaccine and MS. Reviews of these data by panels of
persons with clinical expertise have favored rejection of a causal
association between hepatitis B vaccination and MS (169,170).
Chronic illnesses that have been reported in rare instances
after hepatitis B vaccination include chronic fatigue syndrome
(171), neurologic disorders (e.g., leukoencephalitis, optic neu
ritis, and transverse myelitis) (172–174), rheumatoid arthritis
(175,176), type 1 diabetes (177), and autoimmune disease
(178). No evidence of a causal association between these conditions
or other chronic illnesses and hepatitis B vaccine has
been demonstrated (159,169,170,179–182).
Reported episodes of alopecia (hair loss) after rechallenge
with hepatitis B vaccine suggest that vaccination might, in
rare cases, trigger episodes of alopecia (183). However, a population-
based study determined no statistically significant
association between alopecia and hepatitis B vaccine (184).
No evidence exists of a causal association between hepatitis
B vaccination, including administration of the birth dose, and
sudden infant death syndrome (SIDS) or other causes of death
during the first year of life (185–187). Infant death rates,
including rates of SIDS, declined substantially in the United
States during the 1990s, coincident with an increase in infant
hepatitis B vaccination coverage from <1% to >90% and
implementation of efforts to reduce SIDS through infant sleep
positioning and separation from other persons in bed (188).
The safety of hepatitis B vaccine and other vaccines is
assessed continuously through ongoing monitoring of data from
VSD, the Vaccine Adverse Events Reporting System (VAERS),
and other surveillance systems. Any adverse events after vaccination
should be reported to VAERS; report forms and assistance
are available from CDC at telephone 1-800-822-7967 or at
http://www.vaers.hhs.gov.
Contraindications and Precautions
Hepatitis B vaccination is contraindicated for persons with
a history of hypersensitivity to yeast or to any vaccine component
(92,189–191). Despite a theoretic risk for allergic reaction
to vaccination in persons with allergy to Saccharomyces
cerevisiae (baker's yeast), no evidence exists that documents
adverse reactions after vaccination of persons with a history
of yeast allergy.
Persons with a history of serious adverse events ( e.g., anaphylaxis)
after receipt of hepatitis B vaccine should not
receive additional doses. As with other vaccines, vaccination
of persons with moderate or severe acute illness, with or without
fever, should be deferred until the illness resolves (192).
Vaccination is not contraindicated in persons with a history
of MS, Guillain-Barré syndrome, autoimmune disease (e.g.,
systemic lupus erythematosis or rheumatoid arthritis), or other
chronic diseases.
Pregnancy is not a contraindication to vaccination. Limited
data indicate no apparent risk for adverse events to developing
fetuses when hepatitis B vaccine is administered to pregnant
women (193). Current vaccines contain noninfectious
HBsAg and should cause no risk to the fetus.
Future Considerations
Implementation of the recommendations and strategies in
this document should ultimately lead to the elimination of
HBV transmission in the United States. New information will
have implications for this effort, and adjustments and changes
are expected to occur.
Long-Term Protection and Booster
Doses
Studies are needed to assess long-term protection after vaccination
and the possible need for booster doses of vaccine. The
longest follow-up studies of vaccine protection have been conducted
in populations with an initially high endemicity of HBV
infection (i.e., >8% prevalence of chronic infection) (130).
Implementation of hepatitis B vaccination programs in populations
with a high endemicity of HBV infection has resulted in
virtual elimination of new HBV infections by providing vaccine-
induced immunity to susceptible persons. In these populations,
ongoing exposure of vaccinated persons to persons with
chronic HBV infection might complicate future efforts to assess
long-term hepatitis B vaccine efficacy. Assessment of efficacy
provided by hepatitis B immunization after 15–20 years
will require studies among populations that continue to have
exposures to HBsAg-positive persons ( e.g., communities of immigrants
from highly endemic countries, populations of
injection-drug users, or health-care workers) and studies among
populations with a low prevalence of infection.
Immunization Escape Mutants
Mutations in the S gene of HBV can lead to conformational
changes in the a determinant of the HBsAg protein,
which is the major target for neutralizing anti-HBs. These
variants have been detected in humans infected with HBV,
and concern has been expressed that these variants might replicate
in the presence of vaccine-induced anti-HBs or anti-
HBs contained in HBIG (194,195). Although no evidence
suggests that S gene immunization escape mutants pose a threat
to existing programs using hepatitis B vaccines (196), further
studies and enhanced surveillance to detect the emergence of
these variants are high priorities for monitoring the effectiveness
of current vaccination strategies. |
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