Risk of transfusion associated AIDS by seronegative blood in Thailand: a multicenter report.

Prevention of transfusion associated AIDS (TAA) in Thailand began in 1986 when the HIV infection started to be sharply increased among the general population. The retrospective anti-HIV screening in various blood donor populations by The National Blood Center (NBC) revealed a seroconverted prisoner. Then the use of prisoners, prisoners' blood was not recommended from 1986. In April 1987, the first case of TAA was disclosed. Five months later, anti-HIV screening in all units of blood was firstly introduced at Ramathibodi Hospital (RH) and NBC. From 1989, anti-HIV screening in all units of blood is mandatory nationwide by Ministry of Public Health. Despite the anti-HIV screening, TAA cases transmitted by seronegative blood were gradually reported. Among many Medical Centers, there were 9 and 18 cases of TAA recorded from Chiang Mai and Bangkok areas respectively, since 1985. In addition, several new seroconverters were observed among voluntary blood donors. All of this evidence indicates the existence of blood donation during the early stage of infection, the so-called "window period". At present, HIV-P24 antigen ELISA seems to be the only available technique for mass screening. In 1990, NBC successfully performed a retrospective study on HIV-Ag ELISA screening by obtaining the prevalence of 1/10,000 units of blood. At the same period of time, in RH prospective study, a unit of blood with HIV-Ag only was detected when 3432 units of blood were screened. The HIV-Ag ELISA screening was then performed on every unit of blood routinely since Aug 12, 1991 at RH.(ABSTRACT TRUNCATED AT 250 WORDS)