Trends in donor infection profiles and residual risks of transfusion-transmitted human immunodeficiency virus, hepatitis C virus and hepatitis B virus after the implementation of universal mini-pool nucleic acid testing in Taiwan.

Background and objectives: Universal mini-pool nucleic acid testing (NAT) for human immunodeficiency virus (HIV), hepatitis C virus (HCV) and hepatitis B virus (HBV) in blood donations has been introduced in Taiwan since 2013. This study aimed to evaluate changes in donors' infection profiles and residual risks of transfusion-transmitted infections (TTIs) for these viruses after NAT implementation.

Materials and methods: Donations from 15 January 2013 to December 2023 were included in this study. Residual risks associated with the window period (WP) and occult HBV infection (OBI) were both estimated.

Results: Among 19,756,973 donations, 465, 5592 and 23,534 were confirmed positive for HIV, HCV and HBV, respectively. A high proportion of HBV-positive donations was NAT-yield donations (19.5%), particularly among repeat donors (61.3%). Donor prevalences for these viruses declined regardless of first-time or repeat donors. The residual risks of WP per million donations in 2022-2023 were estimated at 0.08 (95% confidence interval [CI]: 0.02-0.17) for HIV-TTI, 0.31 (95% CI: 0.24-0.55) for HCV-TTI and 26.38 (95% CI: 12.81-50.06) for HBV-TTI, with significant declining trends for HIV-TTI and HBV-TTI since universal NAT implementation. The residual risk of OBI was relatively high yet decreasing, accounting for more than half of the total residual risk for HBV-TTI in 2022-2023.

Conclusion: After NAT implementation in Taiwan, prevalences and residual risks of TTI for HIV, HCV and HBV have declined. Although the residual risk of HBV-TTI remains relatively high, it is comparable to that in other endemic areas, and no cases of TTI from these viruses have been reported since NAT implementation.