A majority of Alaska natives showed signs of protection against hepatitis B virus infection 30 years after receiving a primary vaccination series, suggesting booster doses are not needed, according to published findings.
“We believe that the results of our findings are applicable to children, adolescents and adults vaccinated during hepatitis B catch-up programs and to health care workers vaccinated with either vaccine. Hepatitis booster doses are not currently needed for these groups at 30 years out from primary vaccine series,” Michael G. Bruce, MD, medical epidemiologist, CDC Arctic Investigations Program, Anchorage, Alaska, and colleagues wrote.
Bruce and colleagues evaluated 1,578 Alaska native adults and children from 12 of 15 Alaska communities who were given three doses of plasma-derived HBV vaccine in 1981. The participants were tested for antibody to hepatitis B surface antigen (anti-HBs) levels 30 years after receiving the vaccine series. Researchers wanted to determine the number of participants with anti-HBs levels greater than 10 mIU/mL and to measure the immune response to a booster dose of HBV vaccine in those who had anti-HBs lower than 10 mIU/mL.
Overall, 435 participants were included in the final analysis and split into three groups: those who did not participate in the 22-year study and had no blood drawn (group 1, n = 243), those who did not receive the booster vaccine at 22 years (group 2, n = 129) and those who received a booster dose at 22 years (group 3, n = 63).
Of all the participants, 219 had anti-HBs levels greater than 10 mIU/mL with geometric mean concentrations (GMC) of 13.8 mIU/mL. Participants who received the booster (group 3) had lower GMC compared with those who did not participate (group 1). However, group 3 had higher GMCs than those who did not receive the booster dose (group 2).
Among 56% of participants who responded to the original dose series (n = 243) and did not receive subsequent doses over 30 years, 51% had anti-HBs levels greater than 10 mIU/mL (n = 125). Eighty-eight percent of participants available after follow-up who had anti-HBs level less than 10 mIU/mL responded to a booster dose at 30 days with anti-HBs levels of more than 10 mIU/mL (75/85).
Multivariate analysis of those in group 1 showed that initial anti-HBs level after the primary vaccine series correlated with higher anti-HBs levels at 30 years, according to the research.
In an accompanying editorial, Pierre Van Damme, MD, PhD, of the Centre for the Evaluation of Vaccination at the University of Antwerp, Belgium, stated that the current study shows how immune memory can still be affected after 30 years of initial vaccination.
Pierre Van Damme
“The question that is nearly as old as hepatitis B vaccine itself — how long will immune memory last? — remains to be answered, but the current Alaskan study shows 30 years after initial vaccination that specific immune memory can outlast the persistence of vaccine-induced antibodies,” Van Damme wrote. “The data presented by Bruce et al confirm statements from the World Health Organization, Centers for Disease Control and Prevention and Viral Hepatitis Prevention Board that booster vaccination against hepatitis B for immunocompetent children and adults is not recommended.”
Bruce and colleagues concluded: “Based on anti-HBs level [greater than or equal to 10 mIU/mL] at 30 years and an 88% booster dose response, we estimate that [greater than or equal to] 90% of participants had evidence of protection 30 years later. Booster doses are not needed.” – by Melinda Stevens
Disclosure: The researchers report no relevant financial disclosures.