Detection of West Nile virus in blood donations--United States, 2003.

During the 2002 epidemic of West Nile virus (WNV) in the United States, a total of 23 persons were reported to have acquired WNV infection after receipt of blood components from 16 WNV-viremic blood donors, and an estimated 500 viremic donations might have been collected (B. Biggerstaff, M.D., CDC, personal communication, 2003). Because of the possibility of recurrent WNV epidemics in the United States, blood collection agencies (BCAs) recently implemented WNV nucleic acid--amplification tests (NATs) to screen all donations and quarantine and retrieve potentially infectious blood components. In addition to NAT screening, the Food and Drug Administration (FDA) recommended that BCAs enhance donor deferral questions by specifically asking about fever with headache occurring in the week before donation and defer persons reporting such symptoms. This report describes the NAT screening process for two WNV-viremic donors and presents data summarizing the testing results for approximately 95% of the civilian blood donations collected during late June to early August. These preliminary data suggest that investigational screening tests are effective in identifying viremic donations and preventing the implicated blood components from entering the blood supply.