Seroprevalence of HIV and HTLV in a representative sample of the Spanish population

HIV and HTLV seroprevalence was determined by means of unlinked anonymous t esting of 2144 sera, originally obtained from primary care patients by repr esentative sampling of the Spanish population aged 15-39 years in 1996. HIV -1 seroprevalence was 4.3 per 1000 population in the 15-39 years age group [95 % confidence interval (CI), 1.5-10.7] and 5.6 per 1000 (95 % CI, 1.8-15 .3) in the 20-39 years age group. Seroprevalence proved higher in males and urban residents. No antibodies to HIV-2 and HTLV-I were detected in any of the sera studied. However, presence of antibodies to HTLV-II was confirmed in one serum sample, while HTLV seroreactivity, though detected in another , could not be typed. The two HTLV-positive results equated to a seropreval ence of 1.9 per 1000 in the 20-39 years age group (95 % CI, 0.3-8.6). HIV-1 seroprevalence was consistent with previous estimates yielded by backcalcu lation. The level of HTLV seroprevalence found suggests endemicity.