Evidence for Transmission of Zika Virus by Platelet Transfusion

In this letter to the editor, the authors discussed a report from Brazil of 2 cases of Zika virus (ZIKV) transmission by blood transfusion. A presymptomatic infected individual donated 2 platelet units by apheresis on January 16, 2016. Leukodepleted units were irradiated with 25Gy and transfused to 2 different patients on January 19, a 54-yearold woman with primary myelofibrosis syndrome (or patient 1) and a 14-year-old girl with acute myeloid leukemia who was receiving continuous immunosuppressive therapy following recent haploidentical bone marrow transfusion (patient 2). On January 21, the donor reported a cutaneous rash, retroorbital pain, and pain in both knees that began on January 18. Subsequently, samples were collected 6 days after platelet transfusion for patient 1 and 23 and 51 days after infusion for patient 2. The samples tested positive for ZIKV on reverse transcriptasepolymerase chain reaction assay. RNA molecular sequencing, phylogenetic analysis, and serologic data also confirmed the identity of the infection as ZIKV. Neither patient reported any symptoms associated with ZIKV infection during the investigation. As there is a temporal coincidence, these 2 cases strongly favor platelet transfusion as a source of infection and means of ZIKV transmission.