Epidemiology of Syphilis infections among pregnant women in Tanzania: Analysis of the 2020 national representative sentinel surveillance

Background Syphilis has detrimental effects on the health of the mother and that of the child when pregnant. Understanding its local epidemiology is essential for policies, planning, and implementation of targeted preventive interventions. Using data from the 2020 National Sentinel Surveillance of pregnant women attending antenatal clinics (ANCs) in Tanzania we determined the prevalence and determinants of Syphilis among pregnant women in Tanzania mainland. Methodology The ANC surveillance was conducted in 159 ANC sites from all 26 regions of Tanzania’s mainland from September to December 2020. It included all pregnant women older than 14 years on their first ANC visit in the current pregnancy during the survey period. Counselling for Syphilis was done using standard guidelines at the ANC and testing was done using rapid SD Bioline HIV/Syphilis Duo test kits. Analysis was done using both descriptive statistics to determine the prevalence and characteristics of syphilis, whereas, logistic regressions were used to examine the independent association between syphilis and dependent variables. Results A total of 38,783 women [median age (Interquartile range (IQR)) =25 (21-30) years] participated in the surveillance. Of them, 582 (1.4%) tested positive for Syphilis. A wide regional variation was observed with the highest burden in Kagera (4.5%) to the lowest burden in Kigoma (0.3%). The odds of Syphilis infections were higher among older women and those with no formal education. Compared with primigravids, women with 1-2, those with 3-4 and those with more than four previous pregnancies had 1.8 (aOR=1.8, 95% CI: 1.2-2.5), 2.1 (aOR=2.1, 95% CI: 1.4-3.1) and 2.6 (aOR=2.6, 95% CI: 1.7-3.9) higher odds of syphilis infection respectively. Conclusion Syphilis is still prevalent among pregnant women in Tanzania with a wide regional disparity. Efforts to prevent new infections, screen pregnant women, and treat those infected should be strategized to include all regions and renewed emphasis in regions with high burden, and importantly among women who are multipara, with the low level of education, and advanced age. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement The 2020 National ANC HSS was funded by Ministry of Health through the financial support of the Global Fund for AIDS TB and Malaria. Muhimbili University of Health and Allied Sciences was commissioned to prepare, lead, and manage the survey. The preparation of this manuscript was not funded. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Approval to conduct this study was provided by the MUHAS Institutional Review Board (MUHAS-REC-07-2020-298). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes We cannot at this time share the de-identified data file with the third party owing to the Tanzania Health Research Regulation that requires the third party to sign the Data Transfer Agreement. Data may be shared upon request by any researcher to the Ministry of Health (the owner) and upon fulfilling the regulatory requirements.