Mother to child transmission of hepatitis B virus in the Philippines.

A follow-up study of mother to infant transmission of hepatitis B virus was conducted in the Philippines between 1981 and 1983. The prevalence of HBsAg among 527 mothers was 8.5%. Overall, seven out of 17 (41.2%) infants born to HBsAg carrier mothers became HBsAg positive within the first 12 months of life. The risk of becoming HBsAg positive was about 20 times higher for infants born to HBsAg positive mothers than for infants born to HBsAg negative mothers (OR = 18.9, 95% Ci = 2.0-86.6). The risk was even higher if the mother was a carrier of both HBsAg und HBeAg (OR = 91.0, 95% Ci = 49.2-164.8). However, the risk of transmission was very low if the mother was an HBsAg carrier and anti-HBe positive. It was estimated that mother to infant transmission accounts for about one third of HBsAg positivity at one year of age. The implications of these findings in the planning of vaccination campaigns to prevent HBV infections are discussed.

The relationship of hepatocellular carcinoma and liver cirrhosis to hepatitis B virus infection in the Philippines.

The relationship between hepatitis B virus (HBV) infection and cirrhosis (CIR) and hepatocellular carcinoma (HCC) was investigated. 340 cases with HCC and 99 cases with CIR were compared with the control group which were asymoptomatic age- and sex-matched case. Both HCC and CIR have higher infection rated of HBV and the positivity rated of HBsAg than their controls in both sexes. The positivity rate (74.8%) of HBsAg in HCC is significantly higher than that (58.2%) in CIR. HBeAg is more frequently positive in CIR than in HCC, especially among females. There was no sex difference in HBsAg positive among HCC nor among CIR. Age-adjusted AFP elevation is significantly more frequent in HBsAg-positive HCC than in HBsAg-negative. Both HCC and CIR in the Philippines are closely associated with HBV infection. The association with the infection is stronger with HCC than with CIR. Other causative/contributary factors may be important, especially with CIR. However, the great majority of HCC are probably due to chronic HBV infection, the public health control of which may result in a significant diminution of the malignancy in the country.

Incidence and prevalence of hepatitis B. A community-based survey in the Philippines.

In a rural village in the Philippines, sera were collected from 744 residents and tested for evidence of hepatitis B virus infection. In the subsequent year, every household was visited every other week for a period of three months in an attempt to identify clinically apparent cases. At the end of the year, sera were obtained from 78% of persons initially negative for hepatitis B virus and 97% of those initially positive for hepatitis B surface antigen (HBsAg). Overall, HBsAg was found in 8.8% of the population tested, of whom 86% were still HBsAg-positive at the end of the year. Susceptibility to hepatitis B virus infection declined significantly with age, to only 16% in the age group 50 years and older. No difference in the prevalence of markers by sex was observed. The risk of infection in children appeared to increase if one or both parents were infected, compared with both parents susceptible (odds ratio = 3.3 and 7.6, respectively); the risk increased if older siblings were infected, compared with all older siblings susceptible. The overall incidence rate of hepatitis B virus infection was 3.3% per year. For those aged five years or younger, the incidence rate was 9.2%. None of the seroconverters manifested acute symptoms of infection. Despite the evident clustering in families of persons with hepatitis B virus markers, which is suggested by the prevalence survey, only two of nine incident infections observed were in children with HBsAg-positive close relatives. The findings support the impression that in countries endemic for hepatitis B virus, most new cases occur in the young and are clinically inapparent. Furthermore, screening families of young children for chronic carriers in an effort to identify children at high risk for hepatitis B virus infection would have a low sensitivity in the Philippine setting.

Seroepidemiology of hepatitis B virus in the Philippines.

Hepatitis B virus markers were studied in 2,842 Philippine rural subjects from four villages in 1979-1982. The prevalence of hepatitis B surface antigen (HBsAg) and all markers for hepatitis B virus averaged 12% and 58%, respectively, in these rural populations. It is estimated that five million Filipinos are HBsAg positive. The rural age-specific HBsAg prevalence shows an "early peak" (in persons 3-4-years-old) in two communities and a "late peak" (in persons 30-40-years-old) in the other two communities. Family studies suggest that the prevalence of HBsAg and hepatitis B e antigen (HBeAg) among parents of the young children in an "early peak" and a "late peak" village cannot fully account for the difference in the patterns of prevalence of all markers, or the HBsAg marker. Horizontal intrafamilial and extrafamilial transmission may also be significant. Further research is needed on risk factors for hepatitis B virus infection.

HBV exposure and HBsAg positivity rates in schistosomiasis japonica: study in a Philippine community endemic for both infections.

HBV exposure and HBsAg positivity rate were examined in 561 residents of an area endemic for S. japonicum and 22 additional cases with severe HSS japonica were also included. The differences in HBV exposure and HBsAg positivity rates among the groups without the parasitism, with schistosomiasis japonica and with HSS (53 cases) were not statistically significant. Comparison of the same parameters between those with and without S. japonicum infection according to sex and age groupings did not also show significant differences. Increasing intensity of S. japonicum infection was not associated with either increasing or decreasing HBV exposure and HBsAg positivity. It is postulated that HBV infection does not contribute to the production of HSS japonica mainly because HBV infection occurs at a much earlier age than S. japonicum infection.

Hepatitis B virus profile of hepatocellular carcinoma in the Philippines.

The hepatitis B virus (HBV) profile was investigated in 104 age-grouped hepatocellular carcinoma (HCC) patients and 84 controls from the Philippines. The HCC-control percent positivities of the HBV parameters are: HBsAg: 70-18; anti-HBs: 25-37; anti-HBs: 25-37; anti-HBc: 94-35; HBeAg: 5-2; anti-HBe: 60-30; HBV exposure rate: 97-57; current infection: 80-31. Male HCC anti-HBs positivity is significantly lower than in controls. Female HCC patients' anti-HBs are also lower than controls, but this difference is not statistically significant. Simultaneous presence of HBsAg and anti-HBs was found only in male HCC patients. The mean anti-HBc titer of anti-HBs-positive HCC is higher than that of controls. That of HCC patients negative for both HBsAg and anti-HBs is also higher than the corresponding controls. Anti-HBe positivities of infected and noninfected but previously exposed HCC patients are not significantly different, in contrast to noninfected previously exposed controls whose anti-HBe is lower than those with current infection. The exposure rate prevalence of current infection, and the antibody responses to HBV of HCC patients suggested a close relationship between the two conditions in the Philippines.