[Prevalence of HIV, HTLV, and hepatitis B and C viruses in blood donors in France, 1992-1996].

The prevalence of HIV, HTLV, HBV and HCV infections has been calculated by age and sex of blood donors and not, as generally done, according to the number of donations. This study has been conducted on the basis of two surveys. The first one collected information about the sex and age of the seropositive donors. A second survey, begun in 1992, collected information about the demographic characteristics of blood donors. This population has a higher male to female sex ratio (1:2 versus 1:0) and is younger than the general population. Thus, the prevalence of these viral infections has been determined according to sex, age and type of donors (first-time or repeat) from 1992 to 1996 and the trends have been analysed. The main results are the following: a decreasing prevalence of HIV in first-time donors from 1992 to 1996, more marked in men than in women and in the 18-29 year age group than in the other age groups; a slighter decrease in prevalence of HBV and HCV in first-time donors from 1992 to 1996 with no difference in this decrease between sex and age groups. HBs Ag prevalence in first-time donors was twice as high in men than in women and was highest in donors aged from 40 to 49 years in both sexes. Prevalence of antibodies to HCV in first-time donors was comparable in both sexes but varied greatly with age. In men, a peak was observed in the 30-39 age group and in women, the highest prevalence was seen in the 50-65 age group.