Seroprevalence of IgG antibodies against hepatitis-A infection among individuals aged 6-30 years in India, 2021: a nationwide population-based cross-sectional study.

Abstract

India accounts for one-fifth of the global hepatitis A virus (HAV) infections and half of HAV-related deaths. There is a lack of nationally representative population-based data on the endemicity of HAV to inform vaccination policy. We aimed to estimate the age-specific seroprevalence of HAV infection among individuals aged 6-30 years. We used serum samples collected during the fourth national COVID-19 serosurvey conducted between 14 June and 6 July 2021 to estimate the seroprevalence of HAV infection. The survey was conducted in 70 randomly selected districts across 20 Indian states and one union territory. We tested the serum samples from individuals aged six to 30 years for IgG antibodies against HAV. We estimated the overall and state-specific seroprevalence, along with 95% CIs, for the age groups of 6-10, 11-15 and 16-30 years. We classified the HAV endemicity in India using WHO classification (high, intermediate, low and very low). We tested 14,778 serum samples from individuals aged six to 30 years for IgG antibodies against HAV. Of these, 12,236 (90.0%, 95% CI 88.5-91.4) were found to be reactive. The seroprevalence increased with age, from 74.7% (71.1-77.9) among children aged 6-10 years to 85.2% (82.7-87.4) among those aged 11-15 years and 96.9% (96.3-97.5) among individuals aged 16-30 years. India was categorized as having intermediate endemicity for HAV infection as per the WHO classification. Of the 21 states or union territories included in the survey, 18 had intermediate endemicity. Our study findings indicate an intermediate level of endemicity for HAV infection in India. While these findings support consideration of hepatitis-A vaccination, further evidence on disease burden and cost-effectiveness is needed to inform policy decisions. Gates Foundation & Indian Council of Medical Research.