Syphilis in a blood bank in Argentina: Prevalence trends and risk factors

Worldwide, there has been a worrying increase in the prevalence of syphilis. Blood banks have a major role in monitoring the trend of these events, despite the bias due to the altruistic donation strategy.

To determine the seroprevalence of syphilis and analyse its association with defined risk factors among blood donors at the regional blood center at Hospital Prof. Dr. J. P. Garrahan, period 2016-2022.

Donor screening was performed with treponemal and non-treponemal tests to determine the prevalence of active and past syphilis. Sociodemographic characteristics of donors were analysed and the association with potential risk factors was assessed.

A total of 72 874 donations were processed during the study period. The overall prevalence of specific anti-Treponema pallidum antibodies was 0.69% (95% CI = 0.63-0.75). Active syphilis seroprevalence was 0.30% (95% CI = 0.25-0.33). Not active syphilis seroprevalence was 0.39% (95% CI = 0.35-0.44). Anti-T. pallidum seroprevalence among first-time donations was 1.26% (95% CI = 1.14-1.38) while in repeat donations it was 0.16% (95% CI = 0.12-0.21). In univariate analysis, we found an association between syphilis and having a history of any sexually transmitted infection (OR: 5.09, 95% CI = 2.20-11.70, p < 0.01) and being first-time donors (OR: 3.48, 95% CI = 1.70-7.09, p = 0.0001).

Although the overall prevalence of syphilis is 0.69%, among repeat donors prevalence as low as 0.16% was found. This demonstrates the need to maintain and improve screening strategies and promotion of voluntary, altruistic and repeat donation.