Temporal Trends in the Prevalence of HIV in Blood Donors in Northern Thailand, 1990-1998.

Background: Prevention of transfusion transmissible HIV and other infections relies on selection of low risk donors and screening donors with sensitive assays. Selection of donors at low risk in developing countries with major heterosexual epidemics of HIV has been difficult. However, the prevalence of HIV among blood donors reflects the control of infection in the community and the self exclusion in part of donors who have previously tested positive. Methods: We evaluated the trends in HIV prevalence among 175,251 blood donors in Chiang Mai, Thailand, between 1990 and 1998. This area has had an explosive HIV epidemic beginning in 1988-1998. These data were useful to monitor the safety of the blood supply and the evolution of the epidemic. Results: The overall HIV prevalence was 3.0% in men and 0.96% in women; prevalence was higher in first time than repeat donors. The HIV prevalence peaked at 4.04% in 1991, leveled off at about 3.5% between 1992 and 1994, then declined to 0.68% in 1998. In 1998 HIV prevalence was similar in men and women and volunteer and repeat donors. Conclusions: There has been a substantial decline in the HIV prevalence among blood donors in N. Thailand in the past few years. This decline probably reflects widespread testing for HIV and a decreased HIV incidence due to an effective public health program to prevent incident infections from exposure during commercial sex the, "100% condom program. More effective exclusion of high risk donors may have contributed to the decline. This is an example of improvement in the safety of blood in a developing country experiencing a major AIDS epidemic. [ABSTRACT FROM AUTHOR]