CSU 48/2008: PERSISTENCE OF HEP B PROTECTION IN VACCINEES AFTER 15 YEARS
The developed and developing countries now have more than two decades of experience with vaccination against hepatitis B. Most countries give the primary series of vaccinations, using recombinant vaccine, in infancy.
The two studies summarized here, one each from Alaska and Micronesia, suggest that child vaccination with recombinant hep B vaccine does not provide permanent immunity. Both in developed and in developing countries, this raises the question whether there is justification for a booster shot in adolescence.
Bialek SR, Bower WA, Novak R, Helgenberger L, Auerbach SB, Williams IT, Bell BP.
Division of Viral Hepatitis, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. email@example.com
BACKGROUND: Long-term follow-up studies of populations that received recombinant hepatitis B (HB) vaccination beginning at birth are limited. METHODS: Micronesian adolescents who had received 3 doses of recombinant HB vaccine (Recombivax 5 microg at birth, 2.5 microg at 2 months, 2.5 microg ug at 6 months) and tested negative for antibody to HB core antigen (anti-HBc) 2 years after primary vaccination (baseline testing) were followed up 15 years after primary vaccination. After testing for anti-HBc, HB surface antigen (HBsAg), and antibody to HBsAg (anti-HBs), participants received a booster dose of HB vaccine. An anamnestic response was defined as an increase in anti-HBs concentrations to a level > or = 10 mIU/mL 14 days postbooster. RESULTS: Of the 105 participants, 42 (40.0%) had anti-HBs concentrations > or = 10 mIU/mL on baseline testing. At 15 years, 8 (7.6%) were anti-HBc positive; none were HBsAg positive. Of the remaining 97, 7 (7.3%) had anti-HBs concentrations > or = 10 mIU/mL. Of the 96 who received a booster dose, 46 (47.9%) had an anamnestic response; final antibody concentrations were 10-99 mIU/mL for 17 (17.7%) and > 100 mIU/mL for 29 (30.2%). Participants with anti-HBs concentrations > or = 10 mIU/mL on baseline testing were more likely to have an anamnestic response at 15 years [26/39 (66.7%) versus 20/57 (35.1%); P = 0.003]. CONCLUSIONS: Fifteen years after primary vaccination starting at birth, 8% of participants had evidence of past HB virus infection, but none had chronic infection. Absence of an anamnestic response to an additional vaccine dose, seen in half of participants, might indicate waning immunity.
Hammitt LL, Hennessy TW, Fiore AE, Zanis C, Hummel KB, Dunaway E, Bulkow L, McMahon BJ.
Arctic Investigations Program, Centers for Disease Control and Prevention, Anchorage, AK, USA. firstname.lastname@example.org
BACKGROUND: The duration of protection after hepatitis B vaccination of infants is unknown. We determined antibody to hepatitis B surface antigen (anti-HBs) and response to a booster dose 15 years after vaccination among Alaskan children born to hepatitis B surface antigen-negative mothers. These children had protective anti-HBs concentrations when tested after receiving a three-dose series of 2.5 microg recombinant hepatitis B vaccine starting at birth. METHODS: Participants received 5 microg of recombinant hepatitis B vaccine. Sera were collected at baseline, 10-14 days and 1 month after vaccination, and tested for antibody to hepatitis B core antigen (anti-HBc) and anti-HBs. An anamnestic response was defined as an anti-HBs increase within 15 days, from either undetectable to >/=10 mIU/mL, or, if the baseline concentration was detectable, a 4-fold increase. RESULTS: None of 37 participants (mean age 14.6 years) were anti-HBc positive. An anamnestic response (GMC=254 mIU/mL, range 16-2767 mIU/mL) was observed in 18 (51%) of 35 participants who had sera collected within 15 days after the booster. CONCLUSIONS: In this small study, half of children who had received hepatitis B vaccine starting at birth did not have evidence of immune memory as measured by development of anamnestic responses to booster vaccination. Additional studies are needed to assess whether this indicates susceptibility to infection and whether persons vaccinated starting at birth may benefit from a hepatitis B vaccine booster to maintain long-term protection.