Immune Response and Modeled Duration of Protection Following a Single 60 μg Hepatitis B Vaccine Booster in Susceptible Chinese University Students

Background: Since China incorporated the hepatitis B vaccine into its Expanded Program on Immunization (EPI) in 2002, the first cohort of infants to receive the full vaccination series has now reached college age. As vaccine-induced antibodies gradually wane, this cohort faces a higher risk of infection. Therefore, we assessed their current seroprotection status and evaluated the immunogenicity and short-term antibody kinetics of a single 60 μg booster dose in susceptible individuals, while also constructing a model of expected duration of protection. Methods: In a multicenter study across three Anhui universities, 2988 students were screened for HBV markers. Among them, 160 who tested negative for all five markers received a single 60 μg booster. Antibody titers were monitored for 1–5 months. Results: Serological screening showed 0.33% HBsAg positivity, 36.28% anti-HBs positivity, and 63.02% negativity for all markers, indicating high susceptibility. After the booster, seroprotection rate (SPR) remained >85% throughout follow-up, and anti-HBs geometric mean concentration (GMC) peaked at 1–2 months. Stratified analysis based on immune response status revealed that the proportion of high responders (≥100 mIU/mL) peaked early and then gradually declined, whereas the proportion of low responders (10–99.99 mIU/mL) increased over the follow-up period. A linear mixed-effects model predicted that protective levels (anti-HBs ≥10 mIU/mL) would persist for an average of 32.8 months. Conclusions: A substantial proportion of university students lack protective immunity against hepatitis B. A single 60 μg booster rapidly and effectively induced protection, demonstrating strong immunogenicity. These findings support implementing efficient booster strategies in university settings.