Hepatitis B virus infection in Thai children.
We studied hepatitis B virus (HBV) transmission among 7416 Thai children from 148 schools in Kamphaeng Phet province, a rural part of northern Thailand. Their age ranged from 2 to 16 years (median 9 years). Between May 1991 and June 1992, 61 of 2593 (2.4%) in the cohort of susceptible children acquired anti-HBc immunoglobulin. Forty-seven of the 148 schools had children who acquired anti-HBc. School seroconversion rates to anti-HBc varied from 0% to 23%. There was no correlation between percent of carriers in schools and percent of anti-HBc acquisition. Of the 61 children who acquired anti-HBc, eight (13%) became HBsAg carriers but only two were symptomatic, for a clinical to subclinical infection ration of 1 : 30. One of the two symptomatic children became an HBsAg carrier. Three (38%) of the eight who were persistently antigenemic developed antibody to hepatitis B virus e antigen. Males were 2.5 times (95% CI 1.4-4.3) more likely to acquire anti-HBc than females. Risk factors for acquisition of HBc in Thailand over a 9-month period were examined in a subset of 2412 susceptible children and later in a case-control study of 22 children who acquired anti-HBc and 59 age and sex-matched controls. Risks for acquiring anti-HBc were male gender and a history of bleeding gums. In comparing this study to an earlier pilot study among 9848 children from the same area in Thailand, the yearly antibody acquisition rate to anti-HBc among Thai children dropped from 5.7% in 1989 to 2.4% in 1992. A random sample of children in the pilot study showed that 16% were HBsAg positive and 27% had anti-HBc at the beginning of the study. 34% had markers for either anti-HBc or HBsAg. 12% were repeatedly positive for HBsAg a year later.
Kozik
C A
CA
Department of Virology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.
Vaughn
D W
DW
Snitbhan
R
R
Innis
B L
BL
D000293:Adolescent; D002353:Carrier State; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D018562:Disease Transmission, Infectious; D005260:Female; D006509:Hepatitis B / Q000453:epidemiology / Q000635:transmission* / Q000821:virology; D006510:Hepatitis B Antibodies / Q000097:blood; D006514:Hepatitis B Surface Antigens / Q000097:blood; D006513:Hepatitis B e Antigens / Q000097:blood; D006515:Hepatitis B virus / Q000276:immunology; D006801:Humans; D015994:Incidence; D008297:Male; D016555:Matched-Pair Analysis; D010865:Pilot Projects; D015995:Prevalence; D012307:Risk Factors; D012423:Rural Health; D012737:Sex Factors; D013785:Thailand / Q000453:epidemiology
D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D006513:Hepatitis B e Antigens