Antibody Levels and Protection after Hepatitis B Vaccination: Results of a 15-Year Follow-up
- McMahon, Brian J. MD
- Bruden, Dana L. MS
- Petersen, Kenneth M. MD
- Bulkow, Lisa R. MS
- Parkinson, Alan J. PhD
- Nainan, Omana PhD
- Khristova, Marina PhD, DSc
- Zanis, Carolyn BS
- Peters, Helen BS
- Margolis, Harold S. MD
Background:
The duration of protection afforded by hepatitis B vaccination is unknown.
Objective:
To determine antibody persistence and protection from hepatitis B virus (HBV) infection.
Design:
Prospective cohort study.
Setting:
15 villages in southwest Alaska.
Participants:
1578 Alaska Natives vaccinated at age 6 months or older.
Intervention:
During 1981–1982, participants received 3 doses of plasma-derived hepatitis B vaccine. This cohort was followed annually over the first 11 years, and 841 (53%) persons were tested at 15 years.
Measurements:
Antibody to hepatitis B surface antigen (anti-HBs), markers of HBV infection, and testing to identify HBV variants.
Results:
Levels of anti-HBs in the cohort decreased from a geometric mean concentration of 822 mIU/mL after vaccination to 27 mIU/mL at 15 years. Initial anti-HBs level, older age at vaccination, and male sex were associated with persistence of higher anti-HBs levels at 15 years when analyzed by a longitudinal linear mixed model. After adjustment for initial anti-HBs level and sex, those vaccinated at age 6 months to 4 years had the lowest anti-HBs level at 15 years. Asymptomatic breakthrough infections were detected in 16 participants and occurred more frequently in persons who did not respond to vaccination than those who responded (P = 0.01). Among infected persons with viremia, 2 were infected with wild-type HBV and 4 had HBV surface glycoprotein variants, generally accompanied by wild-type HBV.
Limitations:
The loss of participants to follow-up at 15 years was 47%. However, characteristics of persons tested were similar to those of persons lost to follow-up.
Conclusions:
Hepatitis B vaccination strongly protected against infection for at least 15 years in all age groups. Antibody levels decreased the most among persons immunized at 4 years of age or younger.