A paper published in Transfusion used the, “Transfusion-Transmissible Infections Monitoring System (TTIMS) datasets to investigate contemporary demographic and behavioral risk factors associated with active syphilis infections (ASI) in U.S. blood donors. The study looks at behavioral risk factors for syphilis, revealing key insights. A conceptual framework analysis was also developed to explore determinants in the causal pathways of ASI, including mediators and complex variables that may not be entirely captured by surveys or other traditional research instruments.” The authors explained that, “[d]uring the study period there were 2,249 eligible ASI cases, from whom 130 females and 239 males were interviewed between July 2021 and October 2023.” The study found that the, “age between 40 and 54 years old (compared to 55 and older), Black race (compared to White), lower income, being separated, divorced, or widowed, or being single (compared to married or living together), first-time (FT) donation, having ≥2 male or female sex partners, gay or homosexual orientation, and a history of STI were associated with increased odds of ASI.” This highlights behavioral risk factors for syphilis. The authors also noted that, “donors were probed about having sex while intentionally chemically impaired, a somewhat broader concept than the usual chemsex definition. These exposures have not been previously described in association with syphilis in U.S. blood donors. The potential inclusion of specific questions concerning the use of psychoactive substances to enhance sexual experiences should be explored for inclusion in the DHQ.”
The paper concluded that the, “findings establish a baseline for future comparisons of exposures associated with ASI among U.S. blood donors, and potentially to compare with surveillance efforts from the general population from which blood donors are a subset.” This provides further understanding of behavioral risk factors associated with syphilis infection. The authors wrote, “[o]ur findings may also be used as a reference to refine the donor history questionnaire (DHQ), to implement education/prevention interventions targeting more vulnerable subgroups, and to improve communication between blood collection organizations and donors by informing not only the factors that may predict active syphilis infection, but also the relationship between distal and direct determinants of infection. Future analyses should explore the geographic influences on ASI as well as potential motivators for donation.” The authors explained that limitations of their study included, “[w]e enrolled 16 percent of all eligible cases, and the comparison of enrolled, refused, and lost to follow-up showed significant sociodemographic differences beyond region of residency. The percentage of donors with coinfections was lower among enrolled cases, suggesting that donors with higher risk behaviors were not included; it is possible that some exposures, particularly those concerning sensitive information, were underreported. Because the outcome status was known, underreporting of exposures was potentially differential for cases and controls; our selection strategy may also have failed to select donors with very recent syphilis acquisition, with antibody responses still nonreactive; [and] [o]ur selection strategy may also have failed to select donors with very recent syphilis acquisition.”
Citation: Avelino-Silva, V.I, Bruhn, R.L. Kaidarova, Z. et al. “Factors associated with active syphilis infection in U.S. blood donors.” Transfusion 2025.