Molecular confirmation of transfusion-transmitted dengue virus infection following platelet transfusion in the Chinese mainland.

BACKGROUND: Dengue virus (DENV) is considered an emerging threat to blood safety. While transfusion-transmitted DENV (TT-DENV) cases have been documented, TT-DENV has never been reported in Chinese mainland. In this study, a retrospective investigation was conducted after two patients developed dengue fever (DF) following apheresis platelet (PLT) transfusion from the same healthy donor. METHODS: Blood samples from the recipients and the donor were tested for DENV RNA by nucleic acid testing (NAT). Nonstructural protein 1 (NS1) antigen and anti-DENV immunoglobulin M/G (IgM/IgG) antibodies were detected by ELISA. To confirm transmission, DENV E gene fragments were amplified, and whole-genome sequences were obtained by metagenomic next-generation sequencing (mNGS). RESULTS: Our results revealed that the PLT donor was asymptomatic, tested positive for DENV RNA, and negative for anti-DENV IgM/IgG antibodies at donation. After donation, no dengue-like symptoms was developed. Seroconversion was observed at day 21 postdonation. After receiving the DENV-positive PLT unit, recipient 1 had DF only, while recipient 2 developed DF together with headache, joint/muscle pain, and rash. After transfusion, both recipients were positive for DENV RNA and NS1 while negative for anti-DENV IgM/IgG antibodies. Viral sequences from the donor and recipients were identical and belonged to DENV-2. CONCLUSIONS: To our knowledge, this is the first TT-DENV case reported in the Chinese mainland, revealing the necessity of revising current donor deferral policies and testing strategies that predominantly rely on symptoms and travel history.