Efficacy of a heat inactivated hepatitis B vaccine in male homosexuals: outcome of a placebo controlled double blind trial

The efficacy of a heat inactivated hepatitis B virus vaccine, containing 3 micrograms hepatitis B surface antigen (HBsAg), was studied in a high risk group of 800 susceptible homosexual men by a randomised placebo controlled double blind trial. At the trial end point (21.5 months), 17 hepatitis B virus infections had occurred in vaccinated subjects (attack rate 4.8%) and 56 in subjects receiving a placebo (attack rate 23.8%). This reduction in the incidence of hepatitis B virus infections in vaccinated subjects was highly significant (p less than 0.0001). Two months after the first injection 72.3% of the vaccinated subjects had formed antibodies against hepatitis B surface antigen, and this percentage increased to 89% at four months. Maximum anti-HBs titres were reached five months after the first vaccination, the geometric mean titre being 107.6 mIU. Even vaccinated subjects with a low antibody response (greater than or equal to 1 and less than 10 mIU) were found to be protected from HBsAg-positive infections. The vaccine had no serious side effects.

Screening for syphilis among homosexual men in bars and saunas in Amsterdam

Serological screening of 1627 homosexual men visiting two saunas and two bars in Amsterdam showed that 32.2% were seroreactive for syphilis. The 18-month study period ended in June 1981. Follow-up was possible in 91% (224/245) of subjects with both positive TPHA and VDRL test results; 76 cases of previously undetected syphilis were identified among 75 of the 224 men (incidence rate 4.6%). The rate of previously undetected syphilis declined appreciably during the study period. The cost of identifying one new case of syphilis was Df1577 (pounds 120 or US $ 220).

Hepatitis B among homosexual men in The Netherlands

In 1980-1981 a study for the presence of markers of hepatitis B virus was done among 2, 946 homosexual men living in The Netherlands, mainly in Amsterdam. Serologic evidence of a past or present hepatitis B infection was found in 60.3% of this group, and the prevalence differed significantly among the different age groups. Of the total population studied, 4.8% were positive for HBsAg. This prevalence is very high in comparison to that in the general Dutch population, among whom the prevalence of hepatitis B is low, as is shown by the fact that the prevalence of HBsAg was 0.22% among a large group of Dutch first-time blood donors. Another blood sample was collected two to 20 months after the first sample from 316 male homosexuals who were initially negative for hepatitis B markers. It was found that 36 persons had seroconverted, most of them without clinical manifestations of hepatitis. The annual attack rate of hepatitis B in this group was calculated as 27.6% and differed significantly among the different age groups.

Prevalence of syphilis and hepatitis B among homosexual men in two saunas in Amsterdam

In a pilot study by field-screening in two different sauna baths, a day-sauna and a night-sauna, 318 homosexual men were investigated for syphilis and hepatitis B surface antigen (HBsAg) and its antibody (anti-HBs). Of the 134 visitors to the day-sauna 35.1% were seroreactive for syphilis, four (3%) carried HBsAg, and 95 (70.9%) anti-HBs. Of the 184 visitors to the night-sauna 33.2% were seroreactive for syphilis, 16 (8.7%), carried HBsAg, and 97 (52.7%) anti-HBs. The correlation between seroreactivity for syphilis and the presence of HBsAg amd anti-HBs was statistically significant.

Epidemiological implications of the isolations and intratypic serodifferentiation of poliovirus strains in the Netherlands

From the results of virus isolation and serological studies it can be concluded that poliovirus does not occur endemically in the Netherlands. On the other hand continual importation of poliovirus is demonstrated among children of foreign workers, refugees and adoptive children. A certain part of these imported poliovirus strains appear to be wild type as shown by intratypic serodifferentiation with monospecific antisera. These strains are a continuous danger to non-immunized persons lacking neutralizing antibodies. The intratypic serodifferentiation with monospecific antisera also appears to be applicable for the differentiation of wild poliovirus strains and may therefore be a useful tool in epidemiological studies.

Epidemiology of hepatitis A in Amsterdam, October 1978--December 1979

The epidemiology of hepatitis A was studied in Amsterdam during a 15 month period from October 1978 through December 1979. 349 cases of viral hepatitis were reported of which 135 were serologically identified as hepatitis A. The diagnosis was established by testing a single acute-phase serum sample with ELISA for the detection of hepatitis A IgM antibodies. Most cases were sporadic; there were no outbreaks involving more than three cases. A seasonal variation was recognized with the highest incidence in later autumn and early winter. The peak attack rate was found in the age group of 5--9 and a smaller peak was noticed in the age group of 30--34. Recent exposure to a known case of hepatitis A or to a jaundiced person was the probable source of infection in 27% of the patients; 23% contracted hepatitis A within 7 weeks of visiting a tropical or subtropical country and in 50% no source was found. 50 patients provided stool specimens within 2 weeks of the onset of jaundice. Specimens were examined for the presence of hepatitis A virus antigen by ELISA and seven patients had positive stools, all within the first week of the onset of jaundice.