Immune response to hepatitis B vaccine among children under 5 years in Africa: a meta-analysis

Hepatitis B virus (HBV) infection in Africa is mostly acquired before the age of 5 years through vertical or horizontal routes. While all the countries in the World Health Organization African region have introduced HBV vaccination into their national immunization programs, the rate of protective immune response to HBV vaccine among children in Africa has not been systematically synthesized. In this study, we estimated the HBV vaccine seroprotection rate (defined as anti-HBs titer ≥ 10 IU/L) and the associated factors among under-five children who completed a primary series of HBV vaccination in Africa. We systematically searched PubMed, Web Science, and Scopus databases from inception to May 2022 for potentially eligible studies. The pooled seroprotection rate was estimated using a random-effects model with Freeman-Tukey double arcsine transformation and the associated factors were examined using odds ratio estimated by the DerSimonian and Laird method. From the 1063 records identified, 29 studies with a total sample size of 9167 under-five children were included in the meta-analysis. The pooled seroprotection rate was 89.23% (95% CI 85.68-92.33%, I = 95.96%, p