Syphilis Sero-Positivity by Rapid Plasma Regain Assay Among 29 Million Married Couples Planning a Pregnancy During 2013-18: A Provincial Analysis in Mainland China

Background: Syphilis resurgence is a particular concern for maternal and fetal health worldwide, and an earlier screening and treatment for infected women and partners is of great importance. Here we described provincial sero-prevalence, infection self-awareness, temporal and regional characteristics in mainland China. Methods: A national and population-based study was conducted in mainland China. Married couples intending to conceive within 6 months were recruited during 2013-18. Syphilis screening was performed using rapid plasma reagin (RPR) test. Information on infection awareness and sociodemographic characteristics were collected. R software (version 3.2.2) and ArcGIS (version 10.2) was applied for statistical analyses and geographic mapping. Results: Among enrolled 31955041 couples, 29901308 (93·57%) couples had complete RPR results for both husband and wife. 0·62% (186853/29901308) couples tested husband and/or wife syphilis sero-positivity. Seropositivity among wives (0·38%, 114497) was higher than that among husbands (0·30%, 88515). Intra-couple sero-discordance was significant (P 0·05) with yearly increased infection awareness (P<0.05). Couples residing in southwestern and northwestern China had highest rates, with high infection awareness rate among couples in southwestern China and low rate in northwestern China (P<0·05). After adjusted by annual gross domestic product, syphilis seropositivity decreased along with the higher economic levels (P<0·05). Conclusions: Regional resource allocation is reasonable given the geographic variation of syphilis sero-positivity and infection awareness. Syphilis screening with integrated partner notification is warranted considering sero-discordance among couples. Funding Statement: This study was supported by the National Key Research and Development Program of China (grant no. 2016YFC1000307). Declaration of Interests: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. MS Ma reports National Free Preconception Health Examination Project (NFPHEP) supported by Chinese government, a national nonprofit project which benefits rural reproductive aged population. No other disclosures were reported. Ethics Approval Statement: The Institutional Review Board of Chinese Association of Maternal and Child Health Studies approved the project (IRB201001), and written informed consent was obtained from each participant before enrollment.