Impact of the hepatitis B mass vaccination program in the southern part of Thailand.

Abstract

By 1992, hepatitis B vaccine had been included in the Expanded Program of Immunization (EPI) on a nation-wide scale in Thailand. With the results now available from Songkhla Province in the south of Thailand, we are able to fully evaluate its impact on the prevalence of HBV infection and carrier rate. The population studied comprised 180 randomly selected children aged between 2 months and 15 years who had attended Hat Yai hospital due to any acute illness affecting neither the liver nor the immune system. Their sera were examined for the hepatitis markers HBsAg, anti-HBs and anti-HBc, respectively, using a commercially available test kit. We detected anti-HBs in 106 of the 180 children (58.9%) with its prevalence peaking within the age groups of 0-2 (94.4%) and 3-5 years (75.6%), respectively. Six children, five within the age groups of 6-10 and 11-15 years showed anti-HBc, one of them was diagnosed as a chronic carrier; the sixth one of the age group of 0-2 years most probably displayed passive maternal antibodies. The overall HBV carrier rate amounted to 0.55%. The hepatitis B mass vaccination program has proved highly efficient in protecting newborns from infection and heralds the promise of eventually eradicating hepatitis B virus in the not so far future.