Hepatitis B, tropical ulcers, and immunisation strategy in Kiribati.

The seroepidemiology of hepatitis B was studied in Kiribati (formerly the Gilbert Islands). Six hundred and two (98%) of the population studied showed evidence of current or previous infection. The prevalence of hepatitis B surface antigen was 31% (188/615) and of the e antigen was 9% (58/615). Infection was acquired early in life, and the prevalence of both antigens declined with age. The rates of infection were similar in all age groups examined (0-70) including early childhood. Both hepatitis B surface antigen and e antigen were detected in exudates from tropical ulcers, which may be a source of environmental hepatitis B. Concordance of antigen presence was higher in pairs of siblings than in mother-child pairs. All Gilbertese children should receive hepatitis B vaccine at birth or soon after if the long term consequences of hepatitis B infection are to be minimised.