The relationship of e antigen (eAg) and its antibody (anti-e) to vertical transmission of hepatitis B surface antigen (HBsAg) from chronic asymptomatic HBsAg carrier women to their children was investigated in Taiwan. Sera from 20 of the 62 women studied were positive for eAg (32%); serum from only one woman was positive for anti-e (2%). A total of 85% of the babies born to eAg positive mothers became HBsAg carriers, while only 31% of the babies became carriers when the mother was eAg negative. Maternal e antigenemia correlated with a high HBsAg titer, and both parameters were equally good predictors of vertical transmission.

We evaluated the immunogenicity and efficacy of hepatitis B vaccine (Heptavax-B) in a randomized, double-blind, placebo-controlled trial involving 1311 patients receiving hemodialysis in the United States. After three doses of vaccine (40 micrograms each) had been administered, 63 per cent of the patients were antibody-positive. After correction for possible passive transfer of antibodies by blood transfusion, only 50 per cent of vaccine recipients were considered vaccine responders. The incidence of hepatitis B viral infection during the 25 months of the trial was much lower than had been anticipated and was virtually the same in the vaccine and placebo recipients (6.4 and 5.4 per cent, respectively). Four cases of hepatitis B occurred in patients who had an apparent antibody response to the vaccine, but in each case either antibody had reached low or undetectable levels before hepatitis B surface antigen was detected or the patient had been receiving immunosuppressive therapy. This study did not demonstrate the efficacy of the vaccine in a population of patients receiving dialysis in whom both the rate of antibody response to hepatitis B vaccine and the viral attack rate were low. Other measures to control transmission of hepatitis B virus in dialysis units, including surveillance for hepatitis B surface antigen and isolation of patients who are positive for the antigen, must be continued.

A controlled, randomized, double-blind trial in 1,083 homosexual men from New York confirmed that a highly purified, formalin-inactivated vaccine against hepatitis B prepared from HBsAg positive plasma, is safe immunogenic, and highly efficacious. Over 95% of vaccinated subjects developed antibody against the surface antigen. Vaccine-induced antibody persisted for the entire 24-month follow-up period. The attack rate of all hepatitis B virus infections (excluding conversions of anti-HBc alone) was 3.2% in vaccine recipients compared with 25.6% in placebo recipients (p less than 0.0001). In those who received all three doses of vaccine, of 40 micrograms each, the protective efficacy rate was close to 100%. The vaccine protects against acute hepatitis B, asymptomatic infection, and chronic antigenemia. There is reason to assume that the vaccine is also partially effective when given postexposure.

To evaluate the incidence of post-transfusion hepatitis and factors influencing its occurrence, the Transfusion-Transmitted Viruses Study prospectively followed 1513 transfusion recipients from 1974 through 1979. The attack rate for non-A,non-B hepatitis was 10 per cent. The incidence of hepatitis was directly related to the alanine aminotransferase (ALT) level in blood donors. In recipients of multiple transfusions of blood that had no donor-ALT level above 29 IU per liter the attack rate was 6 per cent or less; at higher donor-ALT levels the attack rate increased progressively, reaching 45 per cent in recipients of units with an ALT of 60 IU or greater. A similar relation was observed among recipients of single units of blood. Moreover, hepatitis developed in 10 of 11 recipients of two units with an ALT level of 45 IU or greater. These data indicate that screening blood for ALT levels would reduce the incidence of non-A,non-B post-transfusion hepatitis.

To determine the incidence of infections with hepatitis B virus (HBV) among Chinese preschool children, 1,510 children (mean age, 29 months) were tested for HBV markers; 15.9% were infected with HBV (7.8% positive for hepatitis B surface antigen [HBsAg] and 8.1% positive for antibody to HBsAg) and 84.1% were susceptible when the children were enrolled in the study. The average length of follow-up was 2.1 years among 1,110 children. Among the 924 susceptible children who were followed up, 10.6% had seroconversions for HBV markers, none of which was associated with clinical illness; the annual incidence of HBV infections was 5.0%. Among the 98 children who experienced HBV infections during the study, 23% became HBsAg carriers, and HBsAg persistence was age-related, with most carriers being among the youngest children infected. In contrast, among the children with HBV markers at the time of enrollment, 118 (49.2%) were HBsAg-positive and 86% were still positive on follow-up. The incidence of HBV infections was significantly associated with the frequency of previous injections.

A sensitive radioimmunoassay technique was used to detect hepatitis B e antigen (HBeAg). A strong correlation was found between HBeAg positivity of the serum of hepatitis B surface antigen (HBsAg) carrier women in Taiwan and the subsequent development of surface antigenemia in their babies. All babies who became chronic HBsAg carriers were born to HBeAg positive women, maternal HBeAg positivity being a better prior indication of chronic antigenemia developing in the baby than the HBsAg titer in the mother's serum.

There is a significant excess of serologic evidence of hepatitis type B infection in two high-promiscuity populations: patients with venereal diseases and their unrelated sexual contacts (15% to 18%) and male, but not female, homosexuals (37% to 51%). Spouses of asymptomatic chronic carriers of antigen had a higher prevalence (26% to 28%) than spouses of noncarriers (10% to 11%); however, the prevalence in the former is relatively low when compared with rates seen in other relatives of carriers. Persons who had a higher-than-average probability of exposure to potentially infective partners or whose patterns of sexual behavior made such exposure more likely (large numbers of sexual partners, long duration of homosexuality, involvement in predominantly anal intercourse) were found to have serologic evidence of hepatitis B more frequently than those with other patterns of sexual behavior. This study showed a strong association between serologic evidence of type B hepatitis and patterns of sexual behavior. However, whether or not transmission of hepatitis type B virus occurs through vaginal intercourse could not be ascertained.

We evaluated the efficacy of hepatitis B vaccine (Heptavax-B) containing only the ad subtype in a randomized, placebo-controlled, double-blind trial among 865 staff members of 43 hemodialysis units in the United States. Surface antibody developed in 92.6 per cent of the subjects after two doses of vaccine and in 96 per cent after the six-month booster. The incidence of infections with hepatitis B virus (with or without hepatitis) was 9.9 per cent in placebo recipients and 2.2 per cent in vaccine recipients (P less than 0.01). The two cases of hepatitis B among vaccine recipients did not occur in subjects in whom antibody had developed. In 81 per cent of the hepatitis events, the virus was of the ay subtype. The indicence of ay virus was 8.2 per cent among placebo recipients and 1.2 per cent among vaccine recipients (P less than 0.005). We conclude that these data confirm the efficacy of the vaccine and demonstrate subtype cross-protection.