Seroprevalence of hepatitis A virus in Mumbai, and immunogenicity and safety of hepatitis A vaccine.

ABSTRACT

OBJECTIVES: Since epidemiologic trends of hepatitis A are changing worldwide, we studied its seroprevalence in Mumbai, which is thought to be a high-endemicity area. The immunogenicity and safety of a hepatitis A vaccine were also studied. METHODS: Six hundred and seventy subjects (456 men; age range 6 mo-60 y) answered a questionnaire on social and medical history. Qualitative analysis of total anti-HAV was performed in all subjects by ELISA. One hundred and seven of 147 anti-HAV negative subjects received hepatitis A vaccine at months 0, 1 and 6. Subjects were followed up (months 1, 2, 6, 7) to look for side-effects and seroconversion. RESULTS: The seroprevalence of HAV was 523/670 (78%); 38% of children < 5 years were anti-HAV negative. Seroprevalence rates of 80% were reached by 15 years. Prevalence was lower in the higher socio-economic group (151/234; 64.5%) compared with the lower socio-economic group (372/436; 85%) (p < 0.001). One month after doses 1, 2 and 3 of the hepatitis A vaccine, seropositivity was 92%, 99% and 100%, respectively. Minor self-limited side-effects occurred in 19.5% of subjects; there were no major side-effects. CONCLUSIONS: The seroprevalence of anti-HAV is high in Mumbai. Seroprevalence is lower in the higher socio-economic groups. The hepatitis A vaccine is safe and immunogenic.