Hepatitis B serologic survey and review of immunization records of children, adolescents and adults in Fiji, 2008–2009

Tatsuhiko Tsukakoshi, Josaia Samuela, Eric V Rafai, Uraia Rabuatoka, Sumihisa Honda, Yasuhiko Kamiya, Corazon C Buerano, Kouichi Morita

In Fiji, hepatitis B (HB) vaccine was introduced into childhood immunization program in 1989 and has been administered as a pentavalent since 2006. This study aimed to: (i) survey and examine the extent to which HB infection continue to occur in children, adolescents and adults in Fiji, and (ii) determine HB coverage rates and timeliness of vaccine administration to children. Serum samples of children, adolescents and adults (aged 6 months to <5 years, 16-20 years, and 21-49 years, respectively) collected between 2008-2009 were tested for serologic markers of HB virus infection namely, HB surface antigen (HBsAg), anti-HBs and anti-HB core antigen (anti-HBc). Health record card of each child was reviewed. None of the participating children (0/432) was positive for HBsAg. Overall prevalence of HBsAg among adolescents and adults was 5.6% (7/124) and 3.2% (12/370), respectively. High prevalence (98.1%) of anti-HBs was observed in children. An estimated 17.4% of adolescents and adults had evidence of past HBV infection (anti-HBc positive), of which 87.2% recovered from infection but the remaining 12.8% developed chronic infection. Percentage of children who completed at least 3 doses of HB immunization was 99.3%, and who received them on schedule was 58.5%. Although sample populations for this study is less robust compared to 1998, the prevalence of HBsAg and anti-HBc in children and adults before and after the implementation of the immunization program is much lower. The findings are a positive step in showing that Fiji's HB vaccine control program is achieving its objectives.