Immunogenicity and reactogenicity of an inactivated hepatitis A vaccine in Indian adults

Back/fTound. In India,a possibledecrease in the prevalence of anti-HAV (hepatitisA virus)antibodiesinadultshasincreased their susceptibilityto HAV infection.We evaluatedthe immunogenicityand reactogenicityof an inactivatedhepatitisA vaccine administered in a 3-injectionprotocol. Methods. Thirty-fivehealthy adult volunteers, seronegative for anti-HAYIgG,wereadministered720 ELISAunits/mlof the inactivatedhepatitisA vaccineintramuscularlyat days0, 30 and 180. Anti-HAV IgG was determined at days 30, 60, 90 and 180 to assessthe efficacyof the vaccine and adverse reactions were noted to evaluate its reactogenicity. Results. The mean (SO) age of the volunteers was 33.1 (12.3) years and the man:woman ratio was 19: 16. An overall seroprotection of 37.2% (13/35) was obtained at day 30, 57.1 % (20/35) at day 60 and 85.7% (30/35) at day 90. By day 180, allthe vaccinees(35/35; 100%) achievedprotective seroconversion.The vaccinein generalwaswelltolerated and no serious side-effectswere observed. Only 8.6% (3/35) of subjects developed minor self-resolvingadverse reactions such as local pain, erythema and/or low-gradefever. Conclusions.The inactivatedhepatitisA vaccinein a threeinjectionprotocol (0, 30 and 120 days)issafe,welltolerated and highlyimmunogenicin adult Indian subjects.