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

Abstract

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 I² 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%, I²: 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; I²: 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; I²: 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.

Keywords: Blood donors; Meta-analysis; Prevalence; Syphilis; Systematic review; Thailand.

Fig. 1

Study flow diagram.

Fig. 2

Forest plot showing the prevalence of syphilis among blood donors in Thailand.

Fig. 3

Geographic distribution of the proportion of syphilis in Thailand. All studies had participants in the age range of 16 to 70 years. *All studies had 100% Thai nationality as participants except for Meepradit et al., 2022 in Mae Sai Hospital, Chiang Rai province (Thai: 4,873; 93.4%; Myanma/Burmese: 344; 6.6%). The template of the map was available at https://commons.m.wikimedia.org/wiki/File:Thailand_location_map.svg. This map template is licensed under the Creative Commons Attribution 3.0 Unported license. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation.

Fig. 4

Forest plot showing the OR of syphilis among male blood donors in Thailand.

Fig. 5

Forest plot showing the odds of syphilis among first-time blood donors in Thailand.