Distribution and Persistence of Hepatitis B Surface Antigen and Antibody in a Melanesian Population1

Abstract

The population of Graciosa Bay, Santa Cruz, British Solomon Islands Protectorate, was tested for HBsAg and anti-HBs in 1973 and 1974. Both the antigen and antibody occurred more often in males, presumably due to a higher exposure rate. None of 28 infants under one year of age had antigen and only one of 50 individuals under two years (2%) did. The prevalence of antigenemia was higher in older children and did not decline with increasing age. This pattern is contrasted to that found in other populations which is characterized by onset during the first year and a decrease in prevalence in older age groups. The ratio of antigenemia prevalence to that of antibody is significantly higher in the population under six years of age (p less than 0.01), indicating that younger infected people tend to be asymptomatic carriers while older individuals tend to have produced antibody. Three of 28 individuals with antigen detectable by immunodiffusion in 1973 had lower levels, detectable only by reversed passive hemagglutination after one year. The age specific prevalence of anti-HBs increases to a peak of 34% in the 15-19 year age group and declines thereafter.

Seroepidemiology of Infection with Hepatitis A and B Viruses in an Isolated Pacific Population

“…The prevalence of HBsAg was highest in the 1O-29-year age group and declined in subjects over 30 years of age. The prevalence of anti-HBs declined in the fourth and subsequent decades of life, a trend that has been noted in other Pacific populations [17][18][19][20]. A higher proportion of males than females showed serological evidence of infection (78.2% vs. 70.7%), and the carrier rate was also higher in this group (12.7% vs. 7.2%).…”

A Serological Survey of Selected Papua New Guinea Blood Donors for Hepatitis B and Related Co-Infections

“…Our study demonstrated a downward trend in HBsAg sero-prevalence from 2003–2018 ( Figure 2 , Table 1 ). This is in accordance with studies done in the Solomon Islands, which demonstrated a decline in HBsAg prevalence from 32% in 1977 [ 21 ] to 25.1% in 1999 [ 25 ] to 21.5% in 2007 [ 26 ]. Similarly, Fiji has seen a decline in prevalence from 17.9% in 1982 [ 22 ] to 0% in children, 5.6% in adolescents and 3.2% in adults in 2009 [ 27 ].…”

“…The mean calculated HBsAg prevalence in this study is 23% (95% CI 23.0–24.0) and is similar to other studies found in the region before an expanded programme for immunization was introduced [ 5 , 21 , 22 , 23 , 24 ]; regional prevalence’s varied from 17.9% in Fiji [ 22 ], 32% in British Solomon Islands [ 21 ] and Kiribati [ 23 ], 42% in Tahiti [ 5 ] and 88% in Tonga [ 24 ].…”

“…Alternatively, isolation of the Pomios, who are mostly accessible only via air and water transport, may have mitigated against spread to this population. Lifestyle was seen to be a factor in two rural populations of New Caledonia [ 34 ], yet a study in Fiji showed high prevalence that appeared not to have been affected by location and lifestyle [ 21 ]. A study in Tonga showed increased new cases of HBV infections in rural dwellers compared to urban and attributed this to a lifestyle in rural settings that predisposed them to increased infection [ 35 ].…”

The prevalence of hepatitis B infection amongst urban and rural populations in Western Samoa

“…Previous studies in Pacific populations have shown that the hepatitis B virus is endemic in the region (Austin, Maquire & Miles, 1974;Blumberg et al 1974;Mazzur & Jones, 1977;Gust, Lehmann & Dimitrakakis, 1979;Wong, Purcell & Rosen, 1979) and has revealed striking variations in the prevalence of infection and of chronic carrier rates amongst different groups (Gust, Dimitrakakis & Zimmet, 1978;Vitarana et al 1978). Numerous suggestions have been made to account for these observations, including inherited differences in response to infection, the effect of differences in child rearing and other social practices and differences in the virus itself.…”