There is currently no test that screens for West Nile virus in donated blood. How great is the risk of infection for people who receive donor blood or organs?
You're right that there's no test that is suitable for screening the entire blood supply. A number of people acquired West Nile from blood transfusion and these transfusions were from donors who donated during the summer, when West Nile virus was active. The risk is going down day-by-day as the number of available units of blood that were collected during the peak time period of risk are being used up.
If somebody needs a blood transfusion or an organ transplant, and they're concerned about the virus, they should discuss it with their doctor. However, I'd like to emphasize that if you need a blood transfusion or transplant, its benefits far outweigh the risk of West Nile virus.
Can you discuss current efforts to develop a screening test?
There are a number of companies that are actively trying to develop tests suitable for screening of the U.S. blood supply. The FDA has expressed a desire to have a blood-screening test available and ready to go by the next transmission season, which is going to start somewhere around June. Whether a screening test can be developed and implemented before that time is a big question right now. Even if a blood screening test were available today, implementing it would still require a huge amount of work. Blood centers need equipment, they have to have people to do it, they have to have a computer system developed to get the test results. It's a huge undertaking.
