Zika, a flavivirus, is transmitted by Aedes mosquitoes, most commonly by A. aegypti. This same vector, in addition to A. albopictus, transmits dengue (another flavivirus) and chikungunya (an alphavirus). Other modes of Zika virus transmission include intrauterine, perinatal, and sexual routes. The contribution of sexual transmission to the overall Zika virus risk is unknown at this time.
Zika virus was first described in Africa and subsequently in Asia. It spread further to cause epidemics in the Pacific starting in 2007 on Yap Island, with subsequent spread in 2013 to French Polynesia and beyond. In 2015, Zika was recognized in Brazil and local (autochthonous) transmission has subsequently been reported in numerous countries and territories in the Western Hemisphere including Mexico, the Caribbean, and Central and South America. In addition, active transmission has been reported in tropical areas including several island countries in the Pacific and Cape Verde in the Atlantic. Travel-associated cases have been reported to the Centers for Disease Control and Prevention for several years, but the only vectorial transmissions in the United States have been in the Commonwealth of Puerto Rico, the US Virgin Islands, and American Samoa.
The risk posed by Zika virus to the blood supply is unclear, but the potential for transfusion transmission of Zika virus was suggested when 2.8 percent of asymptomatic blood donors tested positive for Zika viral RNA during the French Polynesian outbreak. The maximum duration of viremia is unknown, but believed to be 1-2 weeks. Although rigorous proof of transfusion transmission is lacking, there appear to be two credible cases from the epidemic in Brazil.
AABB works closely with the FDA, CDC, and the Council of State and Territorial Epidemiologists to continually assess the latest scientific information and develop appropriate tools and policies to reduce the risk of Zika virus transmission through blood transfusions.
AABB posted an analysis of “Revised Recommendations for Reducing the Risk of Zika Virus Transmission by Blood and Blood Components; Guidance for Industry” published by the Food and Drug Administration on July 9, superseding the guidance document of the same title dated August 2016.
AABB, America’s Blood Centers and the American Red Cross submitted joint comments presenting new information to the Food and Drug Administration (FDA) regarding the universal requirement for individual nucleic acid testing (ID-NAT) for zika virus. The joint comments, include a risk-based approach for use of Minipool (MP)-NAT, using defined triggers for conversion to ID-NAT with return to MP-NAT and request that FDA not delay in issuing final guidance.
Steve Kleinman, MD, AABB’s Senior Medical Advisor, gave a joint statement at BPAC on behalf of AABB, America’s Blood Centers and the American Red Cross supporting the use of MP-NAT screening for ZIKV in all states with conversion to ID-NAT following reports of local transmission, similar to the WNV model currently in use.
AABB has updated its "Circular of Information for the Use of Human Blood and Blood Components" web page following the FDA's approval for new language to be inserted in the November 2013 Circular. The updates have been made to provide the approved statement regarding the newly licensed Zika virus (ZIKV) nucleic acid test (NAT).
On March 13th, FDA posted a statement regarding Zika Virus (ZIKV) that reflects new epidemiological information on the Centers for Disease Control and Prevention (CDC) website. A retrospective analysis identified a potential increased risk to blood and tissue safety for Broward and Palm Beach counties that dates back to June 15, 2016, associated with the movement of donors between Miami-Dade, Broward, and Palm Beach counties. FDA stopped short of recommending “lookback” activities because the potential risk of ZIKV transmission is considered very low for affected collections. However, FDA offered precautionary measures for donations made prior to testing for ZIKV.