First cases of Zika virus-infected US blood donors outside states with areas of active transmission.

Zika virus (ZIKV) is transmitted by Aedes mosquitos and can result in severe congenital and adult neurologic abnormalities. ZIKV has rapidly spread northward through Central America and the Caribbean and autochthonous cases have been identified in the continental United States. High rates of ZIKA RNA positivity were detected in blood donors during previous epidemics. ZIKV transmission by transfused blood from healthy donor components has been a growing concern. Individual-donation aliquots of plasma from volunteer blood donors were tested individually with an investigational Procleix ZIKV assay. Initially reactive samples were tested for ZIKV RNA in plasma and red blood cells (RBCs) and for ZIKV-specific antibodies in serum. A confirmed positive classification required confirmation of RNA and/or detection of ZIKV antibodies in index and/or follow-up samples. Between September 19 and November 30, 2016, a total of 466,834 donations were screened for ZIKV RNA. Five donors (one in approx. 93,000) were reactive for ZIKV RNA by both the Procleix ZIKV assay and supplemental testing. The donations were collected outside areas considered as having active transmission, and all five donors had travel exposures. A lookback case demonstrated no infection despite transfusion of a Zika IgG-positive platelet (PLT) component with probable low levels of ZIKV RNA. This report describes the first ZIKV-positive donors detected outside areas with active transmission. These donors most likely represent travel-acquired "tail-end infections" with prolonged RBC-associated ZIKV RNA. The lack of transmission to the recipient of an apheresis PLT may suggest that these units are not infectious.

Williamson PC ，Linnen JM ，Kessler DA ，Shaz BH ，Kamel H ，Vassallo RR ，Winkelman V ，Gao K ，Ziermann R ，Menezes J ，Thomas S ，Holmberg JA ，Bakkour S ，Stone M ，Lu K ，Simmons G ，Busch MP ... -  《-》

First Zika-positive donations in the continental United States.

Zika virus (ZIKV) has spread in the Americas, including parts of the southern United States, and infection can be associated with serious complications, including congenital brain abnormalities. Probable transfusion transmission of ZIKV has been documented in Brazil. Preemptive testing of blood donations for ZIKV RNA was implemented in southern US states at risk of local transmission using a test approved under a Food and Drug Administration (FDA) investigational new drug application, cobas Zika. Screening was expanded after issuance of an updated FDA guidance. Donations reactive on initial screening were further tested by nucleic acid and antibody tests to determine the donor status. Of 358,786 donations from US states screened by individual donation testing, 23 were initially reactive on cobas Zika. Fourteen of these represented probable ZIKV infection based on reactivity on additional nucleic acid testing or anti-Zika immunoglobulin M. Ten of the 14 donors reported travel to an identified ZIKV-active area within 90 days before donation (median time from end of travel to donation, 25 days; range, 6-71 days). Three donors with travel history also had a potential sexual exposure. Only seven of the 14 donations with probable ZIKV infection were detectable upon 1:6 dilution to simulate minipool testing. The estimated specificity of the cobas Zika test was 99.997%. Screening of donations for ZIKV RNA can interdict ZIKV-infected donors. Donor risk factors include travel more than 4 weeks before donation and sexual exposure. Minipool screening would have detected only 50% of the RNA-positive donations.

Galel SA ，Williamson PC ，Busch MP ，Stanek D ，Bakkour S ，Stone M ，Lu K ，Jones S ，Rossmann SN ，Pate LL ，cobas Zika IND Study Group ... -  《-》

Investigational Testing for Zika Virus among U.S. Blood Donors.

Saá P ，Proctor M ，Foster G ，Krysztof D ，Winton C ，Linnen JM ，Gao K ，Brodsky JP ，Limberger RJ ，Dodd RY ，Stramer SL ... -  《-》

Zika virus RNA detection in asymptomatic blood donors during an outbreak in the northeast region of São Paulo State, Brazil, 2016.

In 2015, there was a large Zika virus (ZIKV) outbreak in Brazil. The proportion of asymptomatic infections is very high, and it is possible for transfusion-transmitted ZIKV (TT-ZIKV) infection to occur. The prevalence of asymptomatic ZIKV infection among Brazilian blood donors during this epidemic outbreak is unknown. Plasma samples obtained between October 2015 and May 2016 from 1393 volunteer blood donors were tested for ZIKV RNA. The viral load was quantified using an in-house standard curve. Additionally, positive ZIKV RNA samples were tested for anti-ZIKV immunoglobulin (Ig)M and anti-ZIKV IgG. Of the 1393 blood samples, ZIKV RNA was detected in 37 (n = 37/1393; 2.7%). The median infection viral load detected was 7714 copies/mL (ranging from 135-124,220 copies/mL). The majority of the positive samples (70.3%) exhibited a viral load of approximately 103 copies/mL. Six samples that were positive for ZIKV RNA were also positive for anti-ZIKV IgM and IgG (n = 6/37; 13.5%). This is the first study evaluating the prevalence of ZIKV RNA among Brazilian blood donors, which was relatively high and might lead to TT-ZIKV infection. It is unclear whether the simultaneous presence of anti-ZIKV IgM and IgG in RNA-positive donations or the viral load influences transfusion transmission of the infection. This study also adds to the global understanding of ZIKV prevalence in blood donors during outbreaks and the transfusion impact of the infection.

Slavov SN ，Hespanhol MR ，Rodrigues ES ，Levi JE ，Ubiali EMA ，Covas DT ，Kashima S ... -  《-》

How do we manage blood donors and recipients after a positive Zika screening result?

Zika virus (ZIKV) is a mosquito-borne flavivirus that is the focus of an ongoing pandemic. ZIKV is notable for its severe neurologic sequelae in babies born to infected mothers. High rates of subclinical infection, as evidenced by the finding of ZIKV RNA in asymptomatic donors, raise concerns of risk to the blood supply. To date, a total of four suspected cases of transfusion-transmitted ZIKV have been reported (all in Brazil), none of which were associated with clinical infection in the transfusion recipients. In 2016, the US Food and Drug Administration issued a guidance mandating national blood donor screening for ZIKV in the United States. Five days after implementation of donor screening at our facility, we encountered a ZIKV-positive donor. We provide a practical approach to donor, recipient, and blood product management in the setting of a positive donor ZIKV result. Such has been informed by the challenges we faced in the workup of a ZIKV-reactive donation and recipient lookback.

Jimenez A ，Shaz BH ，Kessler D ，Bloch EM ... -  《-》