No abstract

Background Evidence for mitigation of transfusion-transmitted dengue informed by surveillance data is lacking. This study evaluated the risk of positive dengue viral (DENV) RNA from blood transfusions during a large outbreak in Taiwan. Methods Serum collected from blood donors living in districts experiencing the dengue epidemic were tested for DENV RNA using a qualitative transcription-mediated nucleic acid amplification assay (TMA). TMA-reactive specimens were further tested for IgM and IgG antibodies, NS1 antigen, and viral RNA by RT-PCR. We estimated DENV RNA prevalence and the number of DENV infections among blood donors. Results A total of 4,976 specimens were tested for DENV RNA, and 21 were TMA-reactive. The detection rate (95% CI) was 0.84 (0.15-4.73), 3.36 (1.31-8.60), and 6.19 (3.14-12.17) per 1,000 donors in districts where the weekly dengue incidence was 5-50, 50-200, and 200 or more per 100,000 residents, respectively. Alanine aminotransferase (ALT) screening only detected 4.4% of TMA-reactive donations. A total of 143 transfusion-transmitted DENV (TT-DENV) infections probably occurred during this outbreak, accounting for 9.2 in 10,000 dengue infections. Conclusions Approximately 0.5-1% of blood donations were DENV RNA positive in epidemic districts. The correlation of DENV RNA rates with dengue incidence may inform the design of effective control measures.