Investigations of West Nile virus infections in recipients of blood transfusions.

CDC, the Food and Drug Administration (FDA), and the Health Resources and Services Administration (HRSA), in collaboration with blood collection agencies and state and local health departments, continue to investigate West Nile virus (WNV) infections in recipients of blood transfusions. During August 28-October 26, CDC received reports of 47 persons with possible transfusion-related WNV infection. Investigations showed that 14 of these persons either did not have WNV infection or did not acquire WNV infection through transfusion. The remaining 33 cases, reported from 17 states, occurred among persons who had confirmed or probable WNV infection and had received blood components in the month before illness onset. To date, evidence that WNV can be transmitted through blood transfusion has been found in six of the 33 cases; investigations are ongoing for the other 27 cases.