Long term Immunogenicity of Single Dose of Live Attenuated Hepatitis A Vaccine in Indian Children — Results of 15-Year Follow-up

OBJECTIVES: To measure anti-HAV antibodies 15 years after a single dose of live attenuated hepatitis A vaccine in Indian children. METHODS: Of the 143 children vaccinated in 2004, 109 were evaluated in 2019, clinically and for anti-HAV antibodies. These children have been assessed clinically every year, and for anti-HAV antibodies in 2004, 2007, 2010 and 2014. RESULTS: Of the 109 children who came for the present assessment, 11 had received additional doses of hepatitis A vaccine in 2004/2007 because of low anti-HAV titre (<20 mIU/mL). In the remaining 98 children, 94 (96%) had seroprotective levels with a geometric mean titre of 79.6 mIU/mL. Seroprotection rate in all 109 children was 86.2%. CONCLUSIONS: Single dose of live attenuated hepatitis A vaccine in Indian children demonstrated robust immunogenicity at 15 years post vaccination.