[Hepatitis and HIV infection in users of illegal drugs]

The prevalence of markers for ongoing or past infections with the hepatitis viruses A (HAV), B (HBV), D (HDV) and C (HCV) and with HIV are analyzed in i.v. drug users. The relevant serological parameters were measured in 1989, 1990 and 1991 in 220 to 380 sera each of drug users who frequented the open drugscene "Platzspitz" in a recreational area in the center of Zürich. The prevalence of viral markers for ongoing and past infections was many times higher in drug users than in the Swiss population. Over the three years the prevalence of HAV-markers rose from 50% to 72%, remained stable for HBV (52%, 57%, 58%) and most probably also for HCV. It slightly declined for HIV from 21% to 18% in one series and from 17% to 2% in another series. 10-34% of all individuals tested showed signs of at least one ongoing infection. Combined infections were frequently observed. The prevalence of viral markers was significantly dependent on the duration of drug use and if needle-sharing was practiced or not. Our data were analyzed in the context of the official notifications of these viral infections and related disorders to the Swiss Health Ministry. The risk of infections with the viruses analyzed here is 100-200 times higher in drug addicts than in the Swiss population. Drug users account for 42 to 52% of all infections (and clinical sequelae) notified in Switzerland. In the light of the fact that drug users also represent a potential source of spread of these viruses into the general population, the prevention effort in drug users should have first priority.