Long-term anti-HBs antibody persistence following infant vaccination against hepatitis B and evaluation of anamnestic response: a 20-year follow-up study in Thailand

Abstract

Hepatitis B vaccine has been available worldwide since the mid-1980s. This vaccine was evaluated in a clinical trial in Thailand, conducted on subjects born to hepatitis B surface antigen positive and hepatitis B e-antigen positive mothers and vaccinated according to a 4-dose schedule at 0, 1, 2 and 12 mo of age and a single dose of hepatitis B immunoglobulin concomitantly at birth. All enrolled subjects seroconverted and were followed for 20 y to assess the persistence of antibody to the hepatitis B surface antigen (anti-HBs) (NCT00240539). At year 20, 64% of subjects had anti-HBs antibody concentrations≥10 milli-international units per milli liter (mIU/ml) and 92% of subjects had detectable levels (≥3.3 mIU/ml) of anti-HBs antibodies. At year 20, subjects with anti-HBs antibody titer<100 mIU/ml were offered an additional dose of hepatitis B virus (HBV) vaccine to assess immune memory (NCT00657657). Anamnestic response to the challenge dose was observed in 96.6% of subjects with an 82-fold (13.2 to 1082.4 mIU/ml) increase in anti-HBs antibody geometric mean concentrations. This study confirms the long-term immunogenicity of the 4-dose regimen of the HBV vaccine eliciting long-term persistence of antibodies and immune memory against hepatitis B for up to at least 20 y after vaccination.

Keywords: challenge dose; hepatitis B; hepatitis B virus; persistence; vaccine.

Figure 1. GMC evolution of anti-HBs antibodies from Month 1 to year 20 post-dose-1 in the unboosted group (LT-ATP cohort for immunogenicity).

Figure 2. Study design. This paper will not present the data on subjects boosted at Year-5 for long-term persistence since number of subjects in this group were low (n = 2), and these results do not provide any clinically relevant information. N, number of subjects in the LT-ATP cohort; N*, number of subjects in the ATP cohort for the challenge phase.