Hepatitis B immunity in teenagers vaccinated as infants: an Italian 17-year follow-up study

Abstract

We assessed the persistence of hepatitis B surface antigen antibody (anti-HBs) and immune memory in a cohort of 571 teenagers vaccinated against hepatitis B as infants, 17 years earlier. Vaccinees were followed-up in 2003 and in 2010 (i.e. 10 years and 17 years after primary vaccination, respectively). When tested in 2003, 199 vaccinees (group A) had anti-HBs <10 mIU/mL and were boosted, 372 (group B) were not boosted because they had anti-HBs ≥10 mIU/mL (n = 344) or refused booster (n = 28) despite anti-HBs <10 mIU/mL. In 2010, 72.9% (416/571) of participants had anti-HBs ≥10 mIU/mL (67.3% in group A vs. 75.8% in group B; p 0.03). The geometric mean concentrations (GMCs) were similar in both groups. Between 2003 and 2010, anti-HBs concentrations in previously boosted individuals markedly declined with GMC dropping from 486 to 27.7 mIU/mL (p <0.001). Fifteen vaccinees showed a marked increase of antibody, possibly due to natural booster. In 2010, 96 individuals (37 of group A and 59 of group B) with anti-HBs <10 mIU/mL were boosted; all vaccinees of the former group and all but two of the latter had an anamnestic response. Post-booster GMC was higher in group B (895.6 vs. 492.2 mIU/mL; p 0.039). This finding shows that the immune memory for HBsAg persists beyond the time at which anti-HBs disappears, conferring long-term protection.

Immune response to hepatitis B vaccine among north Iranian healthcare workers and its related factors

“…Previous studies have shown that the protection given by the HBV vaccine lasts at least 15-20 years [28,29]. Our findings showed anti-HBs titers declined with time, but when adjusted for age, this decline was not significant.…”

Persistence of immunity 18–19 years after vaccination against hepatitis B in 2 cohorts of vaccinees primed as infants or as adolescents in Italy

“…Thus, despite the loss of antibody many vaccinated individuals maintain active immune memory and show a strong anamnestic response following a booster dose of vaccine (the so-called boostability) given up to 20-25 y. [8][9][10][11][12] However other studies, mainly conducted in Asiatic countries, indicate that immune memory starts to wane during the second decade after vaccination still arising the question whether there is a need of a booster dose to maintain long-term immunity. 13,14 The aim of this study was to assess the duration of anti-HBs antibody and immune memory in a cohort of teenagers vaccinated as infants and in a cohort of young adults vaccinated as adolescents, 18-19 y earlier.…”

Characteristics of immune memory 10–15 years after primary hepatitis B vaccination

“…A typical anamnestic response is characterised by a rapid 10-100-fold increase in specific antibodies, which starts 5-8 days after the re-exposure to the antigen and peaks after about 14 days [2][3][4]. HBsAg-specific memory has been shown to persist for at least 15-17 years after immunisation [5][6][7]. Long-term follow-up studies have shown that clinical HBV-disease or HBsAg-carrier status rarely occur among successfully vaccinated individuals, even in the case of anti-HBs titres <10 IU/l [8].…”