Determination of immune memory to hepatitis B vaccination through early booster response in college students

Abstract

The long-term protection of hepatitis B (HB) vaccination has been debated for years. The purpose here was to evaluate the kinetic changes of antibody to HB surface antigen (antiHBs) and define immune memory of the HB vaccine among college students who had previously received full neonatal immunization against HB. In all, 127 college students aged 18-23 years born after July 1984 who had completed HB vaccination and were seronegative for all three HB viral markers, including HB surface antigen (HBsAg), antibody to HB core protein (anti-HBc), and anti-HBs, were recruited. They received three doses of HB vaccine at enrollment, 1 month and 6 months after enrollment. Their anti-HBs titers were assayed at enrollment, 7-10 days, 1 month, 6 months, and 7 months following the first dose of HB vaccine. The anti-HBs seroprotective rates for subjects 7-10 days, 1 month, 6 months, and 7 months postvaccination were 20.5%, 75.6%, 94.5%, and 99.2%, respectively. Those who were seroprotective at 7 to 10 days after one dose of HB vaccine booster developed significantly higher levels of anti-HBs at 1 and 6 months than those not developing seroprotective anti-HBs response at an earlier timepoint. Conclusion: At least one-quarter of HB vaccinees have lost their immune memory to the HB vaccine when entering college. Immune memory to HB vaccine was identified by early seroconversion, which was present in only 20% of vaccinees in the present study. To ensure higher than 90% anti-HBs seroconversion rates, at least 2 doses of HB booster vaccines are recommended for at-risk youths who received complete HB vaccinations in neonatal or infant periods but are seronegative for HBsAg, antiHBs, and anti-HBc in adolescence. (HEPATOLOGY 2010;51:1547-1554 See Editorial on Page 1485. U niversal hepatitis B (HB) immunization has been implemented for more than 20 years in Taiwan and led to remarkable reductions in acute and chronic liver diseases. 1,2The national immunization program of Taiwan was launched in 1984: all neonates or infants born before Nov 1992 received plasma-derived HB vaccines at birth. They all received standard doses of HB vaccines at birth according to the same standard protocol. The coverage rate of HB vaccines during the past 2 decades in Taiwan has been >90% and data show that the national vaccine coverage rates were more than 95% in 2001 and 2002. 3,4 It has shown an efficacy of 78%-87% in decreasing the seroprevalence of hepatitis B surface antigen (HBsAg)Abbreviations: anti-HBc, antibody to hepatitis B core protein; anti-HBs, antibody to hepatitis B surface antigen; BMI, body mass index; GMT, geometric mean titers; HB, hepatitis B; HBsAg, hepatitis B surface antigen.From the

Predictors of Hepatitis B Surface Antigen Titers two decades after vaccination in a cohort of students and post-graduates of the Medical School at the University of Palermo, Italy

“…Several studies confirm that the acquired immunity persists for at least 10 years after vaccination with level of antibodies > 10 mIU/mL, but probably not longer, if vaccination had been performed at neonatal age [6][7]. In several countries in the world, students of faculties of medicine are examined to establish if the vaccination performed in infancy is still protective several decades after HBV vaccinations, because this is a population occupationallyexposed to a higher risk of acquiring HBV infection [8][9][10][11][12][13][14][15][16][17][18][19][20].…”

Prevention of Hepatitis B

“…The proportions of postbooster anti-HBs titer ,10 mIU/mL among 15 -23 yr olds was 24% -28% (Jan et al 2010). In another study, a booster dose of HBV vaccination was administered to 1974 HBsAg-and anti-HBsnegative subjects.…”

Historical Perspectives on the Antaean Animadversion of Vaccine Science in the 21st Century

“…Some suggest that focusing more on individual parents may be more productive than focusing on anti-vaccine groups [74]. Public reluctance to accept vaccines complicates other disease-stimulating factors such as vaccine failures, falling antibody levels from previous vaccinations, and others [63,75,76].…”