Hepatitis B vaccination among the Nicobarese

Considering the high endemicity of hepatitis B infection among the tribes, the Centre initiated a pilot project of hepatitis B vaccination using indigenously developed recombinant DNA vaccine (Shanvac-B) in two of the 12 villages of Car Nicobar Island having a total population of 2376. All the tribal persons aged 45 years or less and residing in these villages were enumerated and their blood samples were screened for HBsAg and anti-HBs. Persons negative for these markers were vaccinated with three doses of hepatitis B vaccine.

Sero-protection rate and geometric mean titre of anti-HBs among vaccinated Nicobarese at different intervals

Vaccinated individuals were followed up for antibody titers and evidence of break-through infections.  Follow-up samples were collected one month after first, second and third dose and thereafter at yearly intervals for a period of three years. Besides, about 1400 children studying in 13 primary schools of Car Nicobar island were vaccinated with hepatitis B vaccine. The vaccine was well tolerated without significant side effects. None of the subjects had any anaphylactic reaction. The sero-protection rates and geometric mean titers of anti-HBs are summarized in Fig. 3.20. Four of the 1096 individuals were positive for HBsAg over a two-year period indicating break-through infection.