Impact of routine hepatitis B immunization on the prevalence of chronic hepatitis B virus infection in the marshall islands and the federated States of micronesia.
BACKGROUND
To evaluate the impact of routine hepatitis B (HB) vaccination on the prevalence of chronic hepatitis B virus (HBV) infection among children in Pacific Island countries where HBV infection was highly endemic, we conducted HB serosurveys during 2000 to 2007 among women of childbearing age born before implementation of HB vaccination and among children born after its implementation.


METHODS
Serum specimens were collected from children aged 2 to 6 years and their mothers in Chuuk, Federated States of Micronesia in 2000, children aged 2 to 9 years and their mothers in Pohnpei, Federated States of Micronesia in 2005, and 5- to 9-year-old children and prenatal clinic patients in 2007 in Republic of the Marshall Islands (RMI). Specimens were tested for HB surface antigen (HBsAg) and antibodies to HB core antigen (total anti-HBc). HB vaccination coverage was determined from health department vaccination registries. We defined chronic HBV infection as the presence of HBsAg.


RESULTS
Birthdose and 3 dose HB vaccination coverage was 48% and 87%, respectively, in Chuuk, 87% and 90% in Pohnpei, and 49% and 93% in RMI. Chronic HBV infection prevalence among children was 2.5% (9/362) in Chuuk, 1.5% (7/478) in Pohnpei and 1.8% (6/331) in RMI. Chronic HBV infection prevalence among women was 9.2% (21/229) in Chuuk, 4.4% (10/229) in Pohnpei, and 9.5% (11/116) in RMI.


CONCLUSIONS
Hepatitis B vaccination has resulted in a substantial decline in chronic infection in children in the Pacific Islands. HB vaccine effectiveness is high in this region, despite challenges in providing HB vaccine at birth and completing vaccination series on schedule.
Bialek
Stephanie R
SR
Division of Viral Diseases, Centers for Disease Control and Prevention, 1600 Clifton Rd, NE, MS A-47, Atlanta, GA 30333, USA. zqg7@cdc.gov
Helgenberger
Louisa
L
Fischer
Gayle E
GE
Bower
William A
WA
Konelios
Mailynn
M
Chaine
Jean-Paul
JP
Armstrong
Gregory
G
Williams
Ian T
IT
Bell
Beth P
BP
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006510:Hepatitis B Antibodies / Q000097:blood; D006514:Hepatitis B Surface Antigens / Q000097:blood; D017325:Hepatitis B Vaccines / Q000008:administration & dosage / Q000276:immunology*; D019694:Hepatitis B, Chronic / Q000453:epidemiology* / Q000517:prevention & control*; D006801:Humans; D007114:Immunization / Q000706:statistics & numerical data*; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008849:Micronesia / Q000453:epidemiology; D008875:Middle Aged; D015995:Prevalence; D055815:Young Adult
D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines