Evidence of protection against clinical and chronic hepatitis B infection 20 years after infant vaccination in a high endemicity region

Abstract

Vaccination against hepatitis B virus (HBV) immediately after birth prevents neonatal infection by vertical transmission from HBV carrier mothers. There is an ongoing debate whether infant vaccination is sufficient to protect against infection when exposed to HBV later in life. We studied 222 Thai infants born to HBsAg -/+ and HBeAg -/+ mothers who were vaccinated with recombinant hepatitis B vaccine at 0-1-2-12 months of age. A subset of 100 subjects received a booster dose at age 5 years. Blood samples collected yearly for 20 years were examined for anti-HBs antibodies and serological markers of hepatitis B infection (anti-HBc, HBsAg, and in selected cases HBeAg, anti-HBe, HBV DNA). During the 20-year follow-up, no subject acquired new chronic HBV infection or clinical hepatitis B disease. During the first decade, possible subclinical breakthrough HBV infection (anti-HBc seroconversion) was only observed in subjects born to HBsAg +/HBeAg + mothers (6/49 [12.2%]). During the second decade, breakthrough HBV infections were detected in all groups (18/140 [12.8%]). Increases in anti-HBs concentrations that were unrelated to additional HBV vaccination or infection were detected in approximately 10% of subjects in each decade. Primary infant vaccination with a recombinant hepatitis B vaccine confers long-term protection against clinical disease and new chronic hepatitis B infection despite confirmed hepatitis B exposure.

Trial registration: ClinicalTrials.gov NCT00240500 NCT00456625.

Fig. 1

Study design.

Fig. 2

(a) Subject who seroconverted for antibodies against HBc during the follow-up period, with anti-HBs booster response. (b) Subject (not boosted at Year 5) with >1 serological marker indicative of hepatitis B infection, unaccompanied by anti-HBs booster response or emergence of antibodies to HBc. (c) Subject who developed detectable antibodies against HBc during the follow-up period without an anti-HBs booster response. (d) Response to possible subclinical breakthrough HBV infection in a low responder after primary and booster vaccination (no booster given at Year 5). In all graphs, the response to administration of a challenge dose of HBV vaccine at Year 20 is evident.