West Nile Virus
Overview
West Nile virus (WNV), a mosquito-borne flavivirus, first appeared in the United States in 1999 among birds and horses, and then among people. At first, WNV was thought to be transmitted to humans only through infected mosquitoes, but in 2002 it was determined that transfusion transmission had caused WNV infection in at least 21 people. In 2006, human cases of WNV were reported in 43 states, with two of the documented cases linked to blood transfusions.
Because 80 percent of people infected with WNV are asymptomatic, the only way to detect infected blood donors is to screen a sample of their blood using nucleic acid amplification tests (NAT). NAT tests have been under development since 2003 and were used initially under IND (investigational new drug) testing. In December 2005, FDA approved the first NAT test to screen for WNV in donors of blood, organs, cells and tissue as well as non-heart beating donors. In 2006, a total of 340 prospective blood donors tested positive when screened for WNV, as reported to the Centers for Disease Control and Prevention’s surveillance program.
AABB works closely with the FDA and CDC to continually assess the latest scientific information and develop appropriate tools and policies to further reduce the risk of WNV transmission through blood transfusions.
Recent Actions
7/25/08
The AABB West Nile Virus Task Force sends comments to the Food and Drug Administration containing specific revisions to a draft guidance document on the use of nucleic acid testing to reduce the risk of transmission of West Nile virus from donors of blood, blood components, and human cells, tissues, and cellular- and tissue-based products and recommending that triggering and detriggering decisions be based on presumed viremic donations instead of initially reactive donations.
4/3/07
AABB issues Association Bulletin #07-02 updating its 2004 recommendations for minimum criteria to trigger conversion from minipool NAT to individual NAT and development of a communication plan for “multisite” triggering.
6/16/06
A Phase 1 clinical trial of a study sponsored by the National Institute of Allergy and Infectious Diseases and the National Institutes of Health shows that a vaccine promising protection against West Nile virus (WNV) is safe and well-tolerated.
6/1/06
AABB launches the West Nile Virus Biovigilance Network, an online tool that tracks reports of presumed viremic donations directly identified by the laboratories performing WNV NAT.