ABSTRACT
BACKGROUND: Hepatitis B virus (HBV) is highly endemic in many of the Pacific Island countries. Four island countries-Cook Islands, Kiribati, Niue, and Tokelau-sought to evaluate the success of their hepatitis B vaccination programs by conducting nationally representative serosurveys among children born post-vaccine introduction. METHODS: Cook Islands, Niue, and Tokelau conducted school-based census serosurveys because of small populations. The Cook Islands tested children in second grade; Niue tested children in early childhood education through sixth grade; and Tokelau tested children in first through sixth grades. Because Kiribati has a much larger birth cohort, it conducted a one-stage stratified serosurvey among first grade students. All four countries tested children using the Alere Determine™ rapid point of care hepatitis B surface antigen (HBsAg) test. RESULTS: In the three smaller countries, no children were seropositive for HBsAg (0/245 Cook Island students, 0/183 Niuean students, 0/171 Tokelau students). In Kiribati, 39 (3.3%, 95% confidence interval 2.4-4.6%) of 1249 students were HBsAg positive. Vaccination data collected in the Cook Islands and Tokelau showed high vaccination coverage in both countries with ⩾95% birth dose coverage and 100% 3-dose coverage. CONCLUSIONS: The Cook Islands, Niue, and Tokelau have made remarkable progress in establishing strong vaccination programs and towards decreasing the burden of hepatitis B among children. Kiribati still needs to improve vaccination coverage to achieve the <1% HBsAg target established by the World Health Organization Western Pacific Region.
