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Questions
and Answers
NIP Answers Your
Questions
Hepatitis A
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General
Questions
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Is
there any evidence that giving Hepatitis A vaccine only (no
IG), to travelers with departure date <4 weeks, increases
the risk of Hepatitis A infection? I believe that Canada recommends
only Hep A vaccine (no IG). Can you comment on this?
Here are the recommendations from the ACIP regarding traveler
vaccination with Hepatitis A vaccine:
"Travelers
who are administered vaccine can be assumed to be protected
by 4 weeks after receiving the first vaccine dose and therefore
should receive this dose at least 4 weeks before departure.
Although according to both vaccines' licensure information,
the first dose can be given at least 2 weeks before departure,
available data suggest that 40%-45% of vaccinated persons might
lack neutralizing antibody at 14 days after receiving the first
dose (see Immunogenicity in Adults on page 19). No data are
currently available regarding the risk for hepatitis A among
persons vaccinated 2-4 weeks before departure. Because protection
might not be complete until 4 weeks after vaccination, persons
traveling to a high-risk area less than 4 weeks after the initial
dose also should be administered IG (0.02 mL/kg), but
at a different anatomic injection site. A second vaccine dose
administered according to the recommended schedule (Tables 5
and 6) is necessary for long-term protection.
Travelers
who are allergic to a vaccine component or who elect not to
receive vaccine should receive a single dose of IG (0.02 mL/kg),
which provides effective protection against hepatitis A for
up to 3 months (Table 4). Travelers whose travel period exceeds
2 months should be administered IG at 0.06 mL/kg; administration
must be repeated if the travel period exceeds 5 months (see
Table 4)." Source: Prevention
of Hepatitis A Through Active or Passive Immunization: Recommendations
of the Advisory Committee on Immunization Practices (ACIP).
(6/26/03)
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Should
a thirty-year-old traveler get the hepatitis A vaccine after
having the disease at 7 years of age?
Once
a person has been infected with hepatitis A, they are immune
and do not need vaccination. However, if there is any doubt
about whether the person actually had hepatitis A, you can either
test for immunity or vaccinate them. Since two doses of vaccine
are needed, testing may be more cost-effective. (6/26/03)
- Is
anti-HAV IgM antibody detectable in serum after vaccination?
Yes,
the presence of anti-HAV IgM is part of the normal immune response
to exposure to hepatitis A virus whether it is wild virus or
inactivated vaccine virus. Anti-HAV IgM is detectable in the
serum about two weeks after vaccination and can continue to
be detected for up to 6 weeks depending on the immune response
mounted and the sensitivity of the test. (6/26/03)
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If
a person developed a severe local reaction after the first dose
of hepatitis A vaccine, should we draw a titer before deciding
whether to give the second dose?
No. Whether a second dose is contraindicated depends on the
nature of the reaction; the response to the first dose is not
a factor. A subsequent dose of vaccine is contraindicated if
the reaction was a life-threatening, anaphylactic-type reaction.
Local reactions, even exaggerated ones, do not contraindicate
subsequent doses. (2/12/03)
Top
Schedule
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If
the 2nd dose of Hepatitis A is given less than 6 months after
the 1st dose it is invalid because it was given before the minimum
interval. But when should this dose be repeated?
The repeat dose should be spaced after the invalid dose by the
recommended minimum interval, which is 6 months in this case.
ACIP General
Recommendations (2/13/03)
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What
are the ages to begin use of the adult formulations of Hepatitis
A & B vaccines. The
adult Hepatitis A dosage is indicated for persons 19 years of
age and older. The adult Hepatitis B dosage is indicated for
persons 20 years of age and older. Twinrix (hepatitis A &
B combination) is licensed for use in persons 18 years of age
and older. (6/26/03)
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If
the adult dose of hepatitis A vaccine is indicated for persons
19 years of age and older and the adult dose of hepatitis B
vaccine is licensed for 20 years of age and older, why is Twinrix
licensed for persons 18 years of age and older?
Twinrix is licensed for persons 18 years of age and older because
this was the population with whom Glaxo SmithKline conducted
their clinical trials and the data which they presented to FDA
with their licensure application. Twinrix contains a pediatric
dose of hepatitis A vaccine and an adult dose of hepatitis B
vaccine. The Immunization Action Coalition has produced a one-page
fact sheet on hepatitis A and B dosages that you may find helpful,
www.immunize.org/catg.d/2081ab.pdf.
(6/26/03)
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