Immunogenicity and safety of live attenuated hepatitis A vaccine: a multicentric study.

OBJECTIVE To evaluate immunogenicity and tolerability of single dose live attenuated injectable hepatitis A vaccine in four metropolitan cities of India. METHODS Live attenuated hepatitis A vaccine was administered to 505 children aged 18 to 60 months in four centers across India. Immunogenicity of the vaccine was assessed by estimation of anti-HAV antibody titer at 6 weeks and 6 months following administration of the vaccine. Safety evaluation of the vaccine was also done during the visits. RESULTS At 6 weeks, 480 subjects (95%) came for the follow-up and 411 (81.4%) subjects reported at the end of 6 months. The geometric mean titer (GMT) of anti-HAV antibody of the subjects who did not have the seroprotective titer at the baseline were assessed at 6 weeks and 6 months which was 81.04 mIU/ml and 150.66 mIU/ml respectively. At 6 weeks, 95.1 % seroconverted and at the end of 6 months, 97.9 % had seroconverted. Both solicited and unsolicited vaccine-induced local and systemic adverse events were insignificant at all the centers, except swelling and induration in a few. CONCLUSION Live attenuated injectable hepatitis A vaccine was immunogenic and tolerable with minimal reactogenecity, in this study of single dose schedule. Safety profile was also satisfactory in the study population.