Low risk of human T‐lymphotropic virus infection in U.S. blood donors; Is it time to consider a one‐time selective testing approach?

Abstract

AbstractBackgroundU.S. blood donors are tested at each donation for human T‐lymphotropic virus (HTLV) antibodies. Depending on donor incidence and other mitigation/removal technologies, a strategy of one‐time selective donor testing should be considered.MethodsAntibody seroprevalence was calculated for HTLV‐confirmed‐positive American Red Cross allogeneic blood donors from 2008 to 2021. Incidence was estimated for seven 2‐year time periods using confirmed‐positive repeat donors having seroconverted in 730 days. Leukoreduction failure rates were obtained from internal data from July 1, 2008–June 30, 2021. Residual risks were calculated using a 51‐day window period.ResultsBetween 2008 and 2021, >75 million donations (>18 million donors) yielded 1550 HTLV seropositives. HTLV seroprevalence was 2.05 antibody‐positives per 100,000 donations (0.77 HTLV‐1, 1.03 HTLV‐2, 0.24 HTLV‐1/2), and 10.32 per 100,000 among >13.9 million first‐time donors. Seroprevalence differed significantly by virus type, sex, age, race/ethnicity, donor status, and U.S. census region. Over 14 years and 24.8 million person‐years of observation, 57 incident donors were identified (25 HTLV‐1, 23 HTLV‐2, and 9 HTLV‐1/2). Incidence decreased from 0.30 (13 cases) in 2008–2009 to 0.25 (7 cases) in 2020–2021. Female donors accounted for most incident cases (47 vs. 10 males). In the last 2‐year reporting period, the residual risk was 1 per 2.8 million donations and 1 per 3.3 billion donations when coupled with successful leukoreduction (0.085% failure rate).ConclusionsHTLV donation seroprevalence for the years 2008–2021 varied by virus type and donor characteristics. Low HTLV residual risk and use of leukoreduction processes support the conclusion that a selective one‐time donor testing strategy should be considered.