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- Understand that hepatitis B vaccination-induced
protective antibodies can last for up to 15 years, but
appear to fall off over time.
- Patients who were vaccinated 10 to 15 years ago,
especially those who were vaccinated as children, may
not be adequately protected. For patients with this
history who are at moderate to high risk of hepatitis
B infection consider quantitative hepatitis B antibody
measurement to determine protective immunity.
- Booster shots may be recommended at some point to
reinforce immunity lost over time. However, there is
not yet a federal hepatitis B booster vaccination
The duration of
immunity to hepatitis B virus (HBV) from plasma-derived
vaccine was generally believed to be around 10 years. However,
rigorous determination of the upper time limit for immunity
has not been carried out. Such information could be useful in
devising vaccination schedules and possibly for developing
public health policy with respect to the rationale for and
timing of booster vaccinations.
McMahon and colleagues at the Centers for Disease Control
and Prevention studied 1578 Alaska Natives vaccinated at age 6
months or older between 1981 and 1982. Subjects received three
doses of plasma-derived hepatitis B vaccine appropriate for
their age, and were tested annually for antibodies to
hepatitis B surface antigen (anti-HBs) and HBV infection
markers for the first 11 years.
Anti-HBs levels decreased in the study population from a
mean concentration of 822 mIU/mL after vaccination to 27
mIU/mL at 15 years. Higher levels of anti-HBs were noted in
males, individuals with higher initial anti-HB levels, and
those who were older at the time of vaccination. After
adjusting for initial anti-HBs level and sex, the lowest HBs
levels at 15 years post-vaccination were observed in those
vaccinated between 6 months and 4 years of age.
Researchers detected asymptomatic breakthrough infections
in 16 participants. Infection occurred more frequently in
vaccine non-responders than in responders (P=.01).
The authors concluded that hepatitis B vaccination protects
strongly against infection for at least 15 years.
One limitation of the study was that only slightly more
than half of the original cohort had the 15-year follow-up
Commenting in the same issue of Annals of Internal
Medicine, Ding-Shinn Chen, National Taiwan University
College of Medicine, wrote that before the McMahon study, the
duration of protection conferred by hepatitis B vaccine was
Chen noted McMahon's observation of a precipitous decline
in antibodies at 15 years in individuals vaccinated at a very
young age. "Therefore, children vaccinated in early childhood
may be more likely to have undetectable levels of anti-HBs in
late adolescence or early adulthood, when the risks of HBV
infection increase because of sexual activity or other social
behaviors," Chen wrote.
Loss of anti-HBs does not necessarily mean loss of
immunity, as the immunologic memory induced by the HBV vaccine
persists even as anti-HBs decline. Further follow-up is
therefore needed to determine if and when booster vaccinations
are necessary in the general population.
Primary source: Annals
of Internal Medicine
McMahon BJ et al. Antibody levels and
protection after hepatitis B vaccination: Results of a 15-year
follow-up. Ann Intern Med. 2005;142:333-341.
Additional source: Annals of
Chen D-S. Long-term protection of
hepatitis B vaccine: lessons from Alaskan experience after 15
years. Ann Intern Med. 2005;142:384-85.