Mapping syphilis surveillance: Insights into blood donation screening practices worldwide

Syphilis is caused by the bacterial spirochete Treponema pallidum and can be transmitted through blood transfusion. However, there have been less than 10 documented transfusion-transmitted cases since World War II. Global data comparing population-level syphilis trends with blood donor reactivity and screening practices are limited. This study aimed to compare syphilis screening practices worldwide and to explore the value of universal donor screening.

A cross-sectional international survey was conducted among blood transfusion professionals. Participants reported data collected between 2018 and 2024 on syphilis prevalence, blood donor screening algorithms and reactivity rates, deferral policies and blood safety interventions. Descriptive analyses were performed by year and geographic region.

Thirty-nine participants from 26 countries across five continents answered the survey. Universal donor screening was reported by 35 of 36 institutions providing policy data, with treponemal assays representing the predominant screening approach. Substantial variation was observed in confirmatory testing, donor deferral criteria and donor re-entry policies. Reactivity rates varied markedly across centres and were higher among first-time donors compared to repeat donors. Institutions with higher syphilis rates generally reported higher donor reactivity. Routine leukoreduction was reported by 66.7% of institutions, while pathogen reduction technologies were routinely used by 36.1%. Most centres apply indefinite donor deferral and have not considered removing screening.

Syphilis screening and donor management practices vary across blood services worldwide despite widespread implementation of universal screening. Local epidemiology, testing strategies and donor eligibility policies contribute to observed differences in donor reactivity and surveillance practices.