A Seroepidemiological Study of the Prevalence of Hepatitis B Infections in a Hyperendemic New Zealand Community

Abstract

The prevalence of hepatitis B surface antigen (HBsAg) and its antibody (anti-HBs) were studied in 93% of the population of the New Zealand township of Kawerau. Sera were collected from 7901 subjects over six months old, and 3318 (42%) had markers of hepatitis B virus (HBV) infections. Five hundred and nineteen (6.6%) were positive for HBsAg and 485 (96.4%) of 503 retested were confirmed as chronic carriers. HBsAg prevalence was 5.4% in the 0-4 years age group but only 1 of 66 children under one year old was positive suggesting that later cross infection, rather than perinatal transmission was the major factor responsible for the high pre-school carrier rate. Total HBV marker prevalence increased dramatically in early school years and peak marker prevalence was 67.7% in the 15-19 year age group. Prevalence of HBsAg was more than four times higher in non-europeans than in Europeans (Caucasians). Other factors significantly associated with hepatitis B virus marker prevalence in children were: number of years spent in Kawerau, which was associated with anti-HBs prevalence; and size of household, which was associated with HBsAg prevalence. Number of siblings was not a significant risk factor over and above the effect of size of household. Factors associated with marker prevalence in adults were: number of years spent in Kawerau, which was associated with anti-HBs; birth in the Northern half of the North Island, which was associated with both HBsAg and anti-HBs; size of household, which was more strongly associated with HBsAg prevalence; and amateur tattoos, which were associated with anti-HBs prevalence but not with HBsAg prevalence.

Serological and clinical outcomes of horizontally transmitted chronic hepatitis B infection in New Zealand Māori: results from a 28-year follow-up study

“…The REVEAL study population was exclusively Chinese, while the New Zealand study was 79% Polynesian (Māori and Pacific Islander Peoples). A high proportion of transmission in REVEAL was vertical, while in New Zealand it is predominantly early horizontal, with a sharp increase in the prevalence of exposure to hepatitis B markers in early childhood, and very few children infected under the age of 1 year 24. In Taiwan, the genotype distribution is predominantly B (60%) and C (40%), while New Zealand is predominately C (40%) and D (40%) 25.…”

Comparison of the immunogenicity of reduced doses of two recombinant dna hepatitis b vaccines in New Zealand children

“…Our studies and published clinical trials with vaccines supplied by manufacturers indicated that good anti-HBs seroconversion rates could be obtained using rDNA vaccines at lower than recommended doses IScheirmann et al., 1987;MiIne et al, 1988b;19891. Nevertheless, it was considered prudent to evaluate the performance of low doses of two licensed commercially available rDNA vaccines in this selected population.…”

“…HBV infections are highly endemic in many parts of New Zealand, with the indigenous Maori and the immigrant Pacific Island groups most seriously affected IBoveington, 1972;Milne et al, 1987;Tobias et al, 19871. At present, all newborn and preschool (0-4 years old) children are offered State-funded protective immunisation against HBV.…”

Impact of the Expanded Program of Immunization against hepatitis B infection in school children in Malaysia

“…Babies of carrier mothers who escape infection at birth are at increased risk of becoming infected by their mothers or other carriers in the family or school in the first decade of life [15]. The higher HBsAg carrier rate in boys may be due to the types of play engaged by boys and specific opportunities to exchange contaminated blood in the family or in the school [16,17].…”