Blood safety: improvements needed in Thailand.

There is still a "... relatively high rate of HIV window-period blood donation in Thailand," according to a multicenter team. The results of their recent survey "... underscore the need to improve blood safety, especially in northern Thailand were HIV rates are substantially higher than in Bangkok" (AIDS 1996; 10: 1157-1162). The Thailand-based team, which included Dr. Timothy D. Mastro of the US Centers for Disease Control and Prevention (CDC), conducted a retrospective analysis using blood samples collected from nearly 60,500 blood donors over a 3-year period. For all repeat donors, Mastro calculated the incidence of HIV infection to be 307/100,000 person-years in 1990. Mastro found that the "... probability of a window-period donation was 38/100,000 donations or 1/2644 donations." However, improvements over time occurred, and this probability decreased by 50% between 1991 and 1993. Mastro also found the risk of HIV seropositivity among one-time donors to be twice as high as the risk calculated for repeat donors. This is of concern because approximately two-thirds of all blood donations in Thailand are from first-time donors. "Although HIV incidence among repeat blood donors in Bangkok has decreased over the last 3 years, it remains at an unacceptably high level," Mastro concluded. Among his recommendations to improve the situation included refinements to donor deferral procedures, improvements in HIV antibody testing procedures, with the addition of more accurate tests, and the development of a Thai national policy to include p24 antigen testing.