FDA Talk Papers are prepared by the Press Office to guide FDA personnel in responding with consistency and accuracy to questions from the public on subjects of current interest. Talk Papers are subject to change as more information becomes available.
| T02-39 | Media Inquiries: 301-827-6242 |
| October 25, 2002 | Consumer Inquiries: 888-INFO-FDA |
The Food and Drug Administration (FDA) today issued guidance designed to protect the safety of the blood supply against West Nile Virus (WNV). This guidance for industry provides recommendations for assessing the suitability of potential donors and for the proper handling of blood products from donors known or suspected to have WNV infections.
The guidance applies to whole blood and blood components intended for transfusion and for use in further manufacturing. It is intended to reduce the risk of WNV through transfusions, particularly in geographical areas where human cases are occurring. FDA is issuing the guidance for immediate implementation.
The guidance provides detailed information to help blood establishments decide which potential donors should be deferred; it also sets forth recommendations about the retrieval and quarantine of blood and blood products from donors who develop WNV illness or infection after donation or are suspected of having WNV infections.
In addition, the guidance describes circumstances in which blood collectors should consider notifying transfusion services of proven or likely WNV infection in a donor so that hospitals can trace recipients of blood components from the affected donor.
Finally, the guidance advises industry to encourage donors to report any illness suggestive of WNV (e.g. fever and flu-like symptoms) within 2 weeks of blood donation if WNV infection is circulating in the community.
The guidance builds on existing blood safety regulations that require blood establishments to defer donors who are not in good health. Since approximately 20 percent of persons with WNV have symptoms ranging from mild symptoms to fever and other flu-like symptoms, donor screening procedures already in place should identify these people. FDA reminded the blood industry of these existing provisions in an alert on August 17, 2002, which was updated October 3.
No additional screening questions are being recommended. Currently there is no practical method to distinguish between the vast majority of donors who may have received mosquito bites from uninfected mosquitoes from the small number who may be infected.
Because no screening tests are currently available for WNV, these recommendations for donor deferral and product retrieval are especially important. FDA is working with industry to facilitate the development and review of possible donor screening tests for WNV. FDA is organizing a scientific workshop on WNV testing on November 4 and 5 in Bethesda, MD.
Recommendations in the new guidance for donor deferral include deferring a potential donor with a medical diagnosis of WNV until 14 days after the condition is resolved and at least 28 days from the onset of symptoms or diagnosis, whichever is later. If a person is asymptomatic and did not have recent WNV symptoms, having a positive antibody test result alone would not be grounds for deferral.
For donors who report symptoms suggestive of WNV infection when cases are known to be occurring in the community, it is recommended they be deferred from donating for 28 days from the onset of illness or 14 days after the condition is resolved, whichever is the later date.
Recommendations are also given in the guidance to quarantine and retrieve any unused components if a donor later reports a medical diagnosis of WNV or if a blood donor is associated with a potential case of transmission to a transfusion recipient. FDA does not recommend these measures when donors report only mild cold symptoms without fever, or if donors only report receiving mosquito bites. In the case of plasma derivatives, such as Factor VIII, quarantine and retrieval are not recommended because the viral reduction processes have been shown to inactivate viruses similar to WNV.
FDA reminds potential donors that donating blood carries no risk of acquiring WNV. In situations where blood transfusion may be life-saving, the benefits of blood transfusion outweigh the risk of WNV infection. Bites from mosquitoes carrying WNV remain, by far, the most common means of transmission. The guidance can be found on FDA's website at http://www.fda.gov/cber/gdlns/wnvguid.htm.
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