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Zika Virus Blood Donor Screening

Zika Virus (ZIKV) is an enveloped, single-stranded RNA arbovirus in the Flaviviridae family (genus Flavivirus), closely related to dengue virus (DENV) and West Nile virus (WNV). Like DENV and chikungunya virus (CHIKV), ZIKV is primarily transmitted by Aedes mosquitoes, most commonly Aedes aegypti.

ZIKV outbreaks have occurred on Yap Island, Micronesia in 2007, French Polynesia in 2013-2014, and the Americas in 2015. The largest outbreaks occurred in Brazil and Colombia in 2016, eventually expanding to at least 91 countries in 2018. The first local mosquito-borne transmission of ZIKV in the United States (U.S.) was reported from Puerto Rico in December 2015, and soon thereafter in American Samoa and the U.S. Virgin Islands. An estimated 13% of the population of Puerto Rico was infected during the 2016 outbreak.

Local mosquito-borne transmission of ZIKV was reported in Florida in July 2016 and in Texas in November 2016. Currently, there are no areas of increased risk for ZIKV transmission in the continental U.S., but the possibility of reintroduction of ZIKV by infected individuals exists in states and territories where Aedes aegypti, and possibly Aedes albopictus mosquitoes exist. ZIKV infection was also documented during the outbreaks to occur through other routes of exposure, including perinatal, intrauterine, sexual, laboratory-acquired and blood-borne transmission. More than 60% of men with symptomatic ZIKV infection have detectable ZIKV RNA in their semen during the first 30 days of onset of illness, with the longest recorded duration of 281 days in one man.

Most people infected with ZIKV are asymptomatic or have only mild symptoms such as fever, maculopapular rash, headache, arthralgia, and conjunctivitis that last up to a week. However, ZIKV infection can occasionally be associated with Guillain-Barré syndrome and severe neurological complications. ZIKV infection during pregnancy can cause microcephaly, severe congenital defects, and infant death.

ZIKV may be detected in serum or plasma for 1to 2 weeks after infection and has been detected for longer periods of time in Whole Blood, red blood cells (RBCs), semen, and urine. ZIKV RNA persists in RBCs and Whole Blood for several months following clearance in plasma and other body fluids. In a study of 150 ZIKV infected individuals in Puerto Rico, the median values for ZIKV RNA persistence were 11-17 days in serum; 6-10 days in urine; and 28-41 days in semen.

The Food and Drug Administration issued its final guidance on Zika virus testing in July, 2018. The guidance states that all blood donations collected in the U.S. and its territories must be tested with a licensed nucleic acid test (NAT) for ZIKV using either mini-pool (MP) NAT or individual donor (ID) NAT. Two FDA licensed test systems are now available for ZIKV NAT; Cobas Zika Virus test on the Cobas 6800 and 8800 sytems and Procleix on the Procleix Panther.

FDA recommends switching from MP NAT to ID NAT, even in the absence of ZIKV- reactive donations, when CDC or state or local health departments identify an area at increased risk for ZIKV transmission that affects a defined geographic collection area. In the event of a ZIKV reactive donation, blood collection establishments should convert to ID NAT within 24 hours of obtains the positive test result.

As an alternative to testing, FDA allows blood establishments to use FDA-approved pathogen reduction technology for platelets and plasma to reduce the risk of ZIKV transmission.

FDA does not recommend pre-donation assessment for ZIKV risk factors for donors of blood and blood components because; most infected persons and their sexual partners are unaware of their risk, the infection is usually asymptomatic, appropriate testing strategies are available travel deferrals are complicated to implement. FDA continues to recommend pre-donation assessment for donors of human cells, tissues, or cellular or tissue-based products (HCT/Ps).


Revised recommendations for reducing the risk of Zika virus transmission by blood and blood components: Guidance for industry.

Petersen, L.R., et al., Zika virus. N Engl J Med 2016; 374(16):1552-63 

Motta, I.J.F., et al., Evidence for transmission of Zika virus by platelet transfusion. N Engl J Med 2016; 375:1101-3. 

Berlaire, D., et al., Zika virus and blood transfusion: the experience of French Polynesia. Transfusion 2017; 57:729-733. 

Mead PS, Duggal NK, Hook SA, Delorey M, et al., Zika virus shedding in semen of symptomatic infected men. New Eng J Med 2018;378:1377-1385. 

Aubry M, Richard V, Green J, et al. Inactivation of Zika virus in plasma with amotosalen and ultraviolet A illumination. Transfusion 2016;56:33-40.

Santa Maria, F., et al., “Inactivation of Zika virus in platelets with amotosalen and ultraviolet A illumination.” Transfusion 2017; 57:2016-2025. 

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