A systematic review and meta-analysis of the prevalence and risk of syphilis among blood donors in Thailand

Despite rising rates of sexually transmitted infections (STIs) in Thailand, including syphilis, data on its prevalence and associated risk factors among blood donors remain scarce. This systematic review and meta-analysis aimed to estimate the prevalence of syphilis and identify the key risk factors among blood donors in Thailand to inform targeted interventions for enhanced blood safety.The study protocol was registered in PROSPERO (CRD42024560215) and conducted following PRISMA guidelines. Comprehensive searches were performed across major databases, including ProQuest, Journals@Ovid, Embase, Scopus, PubMed, and MEDLINE, to identify relevant studies. A random-effects model was used to calculate the pooled prevalence and odds ratios (ORs) for syphilis risk factors. Heterogeneity was quantified using the I-2 statistic, and meta-regression and subgroup analyses were employed to explore potential sources of heterogeneity. Publication bias was assessed using funnel plots and Egger's regression test. A total of 23 studies involving 1,142,910 blood donors were included. The pooled prevalence of syphilis among blood donors in Thailand was 0.42% (95% CI 0.27-0.66%, I-2: 99.3%, number of infections: 6,173), with a decreasing trend over time. Male donors were significantly more likely to have syphilis (P < 0.0001; pooled OR: 1.76; 95% CI 1.53-2.03; I-2: 34.2%, 651,019 participants). First-time donors also had an elevated risk of syphilis (P = 0.02; pooled OR: 2.02; 95% CI 1.10-3.70; I-2: 94.0%, 215,245 participants). Additionally, the analysis revealed a significant association between increasing age and higher syphilis risk among blood donors. The systematic review and meta-analysis indicated that syphilis prevalence among blood donors in Thailand is declining; however, male and first-time donors, as well as older age groups, remain at higher risk. To enhance blood safety, targeted interventions are needed, including refining donor screening questionnaires, expanding educational campaigns for high-risk groups, and incorporating advanced screening technologies. Strengthening and regularly updating national screening policies will ensure the effective mitigation of syphilis transmission among blood donors in Thailand.