Transfusion-transmissible coinfections among US blood donors.

Background: Transfusion-transmissible infection (TTI) prevalence among US blood donors has been widely documented. Here we estimate the prevalence of donors presenting with ≥2 TTIs (multiple infections past or present referred to as coinfections) and describe their demographics and associations.

Methods: Data from the Transfusion-Transmissible Infections Monitoring System were compiled for October 2020-September 2023 (3 years). Prevalence per million donations (pmd) was calculated for each TTI coinfection combination with demographic characteristics summarized. The odds of each TTI coinfection combination were estimated using logistic regression. Reactivity by NAT and/or serology (HIV, HBV, and HCV) defined donors as consensus positive (CP) for each infection while serology-based algorithms defined syphilis CP and the subset with active syphilis infections (ASIs).

Results: About 22 million donations were included, with 212 coinfections (9.7 pmd). Around 2% of donations positive for any TTI (n = 10,516) were coinfections. Coinfection prevalence per TTI combination ranged from 0.3 pmd for HIV CP and HCV CP, to 4.3 pmd for HIV CP and syphilis CP. There were high proportions of coinfections from donors who were male, aged 25-54 years, white or black, first time, and residing in the southern US Census Region. The odds of a second TTI occurring in an individual donor with a TTI ranged from 23 (95% CI: 13, 41) times more likely for HBV CP and ASI to 395 (95% CI: 298, 524) times more likely for HIV CP and ASI.

Conclusions: Coinfections are relatively uncommon among blood donors in the United States; however, associations exist among HIV, HBV, HCV, and syphilis infections.