Skip to main content
  • Poster presentation
  • Open access
  • Published:

Risk factors and epidemiology of human T-lymphotropic virus types 1 and 2 in US blood donors

Blood donations in the US are routinely screened for markers of human T-lymphotropic virus (HTLV). Seroprevalence and risk factors associated with HTLV-1 and -2 infection from the US Retrovirus Epidemiology Donor Study (REDS-II) Transfusion-Transmitted Viral Infection (TTVI) Rate and Risk Factor Study are reported. Among 14,809,334 blood donations screened during 2011-2012, 516 HTLV confirmed seropositive cases were identified, with an overall prevalence of 3.5 infections per 1,0 donations (95% CI: 3.2-3.8). A case-control study of risk factors from 90 donors with serology-confirmed HTLV-1 infection, 102 with HTLV-2 (cases), and 1,587 donors with false-positive results (controls) was conducted. Frequencies and adjusted odds ratios (AORs) from separate multivariable logistic regression analyses for HTLV-1 and -2 cases compared to controls are reported. Mean age was 48.0 (SD: 12.4), 52.3 (SD: 11.0) and 41.7 (SD: 15.7) years for HTLV-1, HTLV-2 cases and controls, respectively. Being a first-time donor, older, non-white, non-Hispanic female were significant demographic factors associated with both infections. HTLV-1 cases were more likely than controls to be Black (AOR: 13.3, 95% CI: 6.1-29.2), born outside of the US (AOR: 8.6, 95% CI: 4.0-18.4), have migrated (family or self) from an endemic area (AOR: 1.8, 95% CI: 1.2-2.7), report sex with an IDU (AOR: 10.9, 95% CI: 3.6-33.4) or have multiple partners (AOR: 3.1, 95% CI: 1.5-6.1). HTLV-2 cases were more likely to be Black (AOR: 15.4, 95% CI: 6.9-34.3), Native Americans (AOR: 10.7, 95% CI: 1.5-77.0), report sex with an IDU (AOR: 27.2, 95% CI: 9.7-75.8) or have multiple partners (AOR: 2.9, 95% CI: 1.5-5.7). US blood donors with HTLV-1 or -2 infection present with the known risk factors. Migration from endemic areas is mainly associated with HTLV-1 infection, while HTLV-2 is associated with Native American donors. Sexual risk behavior and IDU continue to be risk factors for both viruses.

Author information

Authors and Affiliations


Rights and permissions

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Vahidnia, F., Stramer, S.L., Kessler, D.A. et al. Risk factors and epidemiology of human T-lymphotropic virus types 1 and 2 in US blood donors. Retrovirology 12 (Suppl 1), P84 (2015).

Download citation

  • Published:

  • DOI: