Current Syphilis Research Articles

Current syphilis infection in virally suppressed people living with HIV: a cross-sectional study in eastern China.

Antiretroviral therapy (ART) has been shown to reduce human immunodeficiency virus (HIV) viral replication and ultimately achieve viral suppression and eliminate HIV transmission. However, little is known about the impact of viral suppression on high-risk behaviors and sexually transmitted infections (STIs). This study aimed to assess the rates of current syphilis infection in virally suppressed people living with HIV (PLWH) and whether with the duration of ART can reduce the current syphilis infection in eastern China. We conducted a cross-sectional survey of PLWH in Zhejiang Province, China, in 2022. PLWH who were on ART >6 months and were virally suppressed (viral load <50 copies/mL) were included in the study. Data were collected from the National Epidemiological Database of Zhejiang Province and all participants were tested for viral load and current syphilis. Multivariable logistic regression was used to identify risk factors associated with current syphilis infection. A total of 30,744 participants were included in the analysis. 82.7% of participants were male, the mean age was 44.9 ± 14.1 years, 84.9% had received ART in a hospital setting, the mean time on ART was 5.9 ± 3.1 years and 5.6% of participants were infected with current syphilis. Multivariable logistic regression showed that being male [adjusted odds ratio (aOR): 2.12, 95% confidence interval (CI): 1.69-2.66], high level of education (aOR: 1.23, 95% CI: 1.02-1.49), homosexual route of HIV infection (aOR: 1.80, 95% CI: 1.60-2.04), non-local registered residence (aOR: 1.29, 95% CI: 1.11-1.51), had history of STIs before HIV diagnosis (aOR: 1.95, 95 % CI: 1.75-2.18) and treatment provided by a municipal hospital (aOR: 2.16, 95% CI: 1.31-3.55) were associated with increased risk of current syphilis infection. Being married (aOR: 0.67, 95% CI: 0.58-0.76) was associated with a decreased risk of current syphilis infection. Our findings revealed a high rate of current syphilis infection among virally suppressed PLWH in eastern China. Duration of ART did not reduce the prevalence of current syphilis infection. Targeted interventions to reduce current syphilis infection should be prioritized for subgroups at higher risk.

Maternal Syphilis Leading to High Efficiency In Utero Transmission of Antiretroviral Resistant HIV: Intersection of Two Pandemics.

Testing for syphilis and HIV is indicated in prenatal care in the United States. Effective antiretroviral therapy during pregnancy reduces mother-to-child HIV transmission (MTCT) to less than 1%. Syphilis infection in pregnant women with unsuppressed HIV increases the risk of MTCT, usually in utero. The incidences of syphilis in women of childbearing age and corresponding congenital syphilis are increasing in the United States. We report 3 cases of in utero HIV transmission associated with maternal syphilis that occurred during the ongoing syphilis epidemic. All 3 women had untreated HIV infection and active syphilis with placentitis during late pregnancy. Their newborns were found to have symptomatic congenital syphilis and HIV infection from in utero transmission. The babies' antiretroviral resistance patterns were nearly identical to their mothers'. When untreated syphilis and uncontrolled HIV coincide in pregnancy, there is a high likelihood of in utero mother-to-child HIV transmission. The current syphilis epidemic in the United States may lead to an increase in MTCT.

Evaluation of rapid diagnostic test kits for detection of Treponema pallidum antibody.

Rapid syphilis testing plays a crucial role in global health strategies, addressing the urgent need for prompt and accurate diagnostics, especially in settings with limited resources. Despite their practical utility, these tests often lack thorough validation, leading to concerns about their efficacy and reliability. This study aims to evaluate two prototypes of the Onsite Syphilis Ab Combo Rapid Test (Fd and Ff) and compare their performance with the established chemiluminescent microparticle immunoassay (CMIA) method. Employing a reverse algorithm approach, the study analyzed 450 serum samples, including those from syphilis patients, healthy individuals, and cases with potential cross-reactions. Results of the rapid test kit were then correlated with CMIA findings, RPR, and TPPA titers. The results showed that prototype Fd exhibited a sensitivity of 100.0%, specificity of 98.8%, positive predictive value (PPV) of 8.4%, negative predictive value (NPV) of 100.00% and accuracy of 98.8%. Similarly, prototype Ff exhibited sensitivity of 100.0%, but with a slightly higher specificity of 99.6%, PPV of 21.5%, NPV of 100.0% and accuracy of 99.6%. Moreover, both prototypes Fd and Ff of the Onsite Syphilis Ab Combo Rapid Test demonstrated significant efficacy diagnostic tool, offering clear and straightforward interpretation for clinicians in varied CMIA, RPR and TPPA titer scenarios. The Onsite Syphilis Ab Combo Rapid Test prototypes, Fd and Ff, demonstrated high sensitivity and specificity, comparable to CMIA methods. The effectiveness highlights their suitability for syphilis screening, particularly in non-laboratory settings or situations requiring immediate results. The validation of these prototypes supports their integration into current syphilis diagnostic algorithms, potentially contributing to improved public health outcomes.

Evaluation of Automated Processing of Electronically Reported Serological Tests for Syphilis Using Current and Historical Syphilis Results Compared With Traditional Reactor Grid Processing in Florida.

Syphilis in Florida increased 49% from 2016 to 2020. Moreover, many serological tests for syphilis (STS) do not indicate current infection. Traditionally, syphilis surveillance systems used reactor grids, a method for prioritizing STS for investigation based on age, nontreponemal titer, and/or sex. In 2022, Florida's sexually transmitted disease surveillance system implemented an automated method for processing electronically reported STS (eSTS), expanding upon the reactor grid, using an individual's current STS (treponemal and nontreponemal), treatment history, and historical STS results aiming for more efficiently processing eSTS. We compared the new method of processing eSTS results against the reactor grid and determined potential value in time/cost savings of this change. All eSTSs (n = 4144) from January 2, 2023 to January 8, 2023, were compared by how the logic-based method processed test results versus how the reactor grid processed test results. Each method was compared using measurements of accuracy (e.g., sensitivity/specificity). Time and cost savings in eSTS processing were estimated. Using the surveillance case definition as reference, the accuracy of the logic-based method for processing eSTS was nearly double (82.3% vs. 43.6%), had greater specificity (79.0% vs. 33.0%), and increased positive predictive value (47.5% vs. 22.0%) when compared with the reactor grid method. Sensitivity (99.5% vs. 98.6%) and negative predictive value (99.9% vs. 99.2%) remained similar. The logic-based method is estimated to save 7783 hours annually (~$185,000). Processing eSTS based on current and historical STS results is significantly more accurate than using a reactor grid. Moreover, these improvements save time and resources that can be better allocated to other program prevention activities.

Evaluating the effect of the plan of national syphilis control in controlling the syphilis epidemic in Jiangsu, China 2010-2020.

Starting in 2010, the Chinese government initiated a 10-year syphilis control plan, called the national syphilis control plan (NSCP), to address the emerging threat of syphilis. We aimed to evaluate the effect of the NSCP plan on syphilis control in Jiangsu, China. The temporal trends of syphilis incidence, prevalence and rate of condom use were estimated by Joinpoint regression with average annual percent change (APC) and average annual percentage (APPC). A Chi-square test was conducted to analyze the outcomes in different subgroups. ArcGIS was used to analyze the spatiotemporal distribution of syphilis incidence. Geographically, early and congenital syphilis incidence decreased significantly in all areas of the province during the period of NSCP. Early syphilis incidence decreased from 21.1 to 8.8 (APC: -7.5, 95%CI: -8.6, -6.5, p < 0.001) per 100,000 people, and congenital syphilis decreased from 63.6 to 4.1 (APC: -14.8, 95%CI: -20.8, -8.4, p < 0.01) per 100,000 newborns from 2010 to 2020. Also, syphilis prevalence reduced from 13.4 to 3.8% (APC: -8.7, 95%CI: -12.1, -5.0, p = 0.001) among men who have sex with men, from 5.3 to 1.7% (APC: -7.9, 95%CI: -11.7, -3.8, p = 0.002) among female sex workers and remained under 1.0% with slight variations among pregnant women (APC: 0.3, 95%CI: -4.3, 5.1, p = 0.877) from 2010 to 2020. 0.2% (2,436) of pregnant women who received free syphilis testing during pregnancy were diagnosed with current syphilis infection, and 97.0% (2,555) of newborns in the province were delivered to women diagnosed with syphilis. 91.8% (2,346) of live babies and about 90% of diagnosed patients received complete standard syphilis diagnosis and treatment services. Trends of early syphilis incidence and syphilis prevalence show a considerable decreasing trend among almost all the key populations after implementing NSCP. Congenital syphilis has significantly decreased as well and hence, the NSCP program should be sustained and strengthened to control the syphilis epidemic in China further.

Factors influencing treatment status of syphilis among pregnant women: a retrospective cohort study in Guangzhou, China

BackgroundMany syphilis infected pregnant women do not receive treatment, representing a major missed opportunity to reduce the risk of syphilis-related adverse pregnancy outcomes. This study explored correlates of treatment among pregnant women with syphilis in Guangzhou, China.MethodsPregnant women with a diagnosis of syphilis in Guangzhou between January 2014 and December 2016 were included. Information of syphilis treatment and correlates were extracted from a comprehensive national case-reporting system. Multivariate logistic regression was used to identify the correlations between information on the demographic characteristics, previous history, clinical characteristics about current syphilis, information of diagnosing hospital, and receiving no treatment or inadequate treatment among syphilis-seropositive pregnant women. A causal mediation analysis was used to explore the potential mediating role of the timing of syphilis diagnosis in the correlates.ResultsAmong 1248 syphilis-seropositive pregnant women, 379 (30.4%) women received no treatment or inadequate treatment. Migrant pregnant women (adjusted OR = 1.83, 95% CI: 1.25–2.73), multiparous participants (adjusted OR = 3.68, 95% CI: 2.51–5.50), unmarried participants (adjusted OR = 3.21, 95% CI: 1.97–5.28) and unemployed participants (adjusted OR = 2.43, 95% CI: 1.41–4.39) were more likely to receive no treatment or inadequate treatment. Participants who with history of syphilis infection (adjusted OR = 0.59, 95% CI: 0.42–0.82) and with high school and higher education participants (adjusted OR = 0.69, 95% CI: 0.49–0.97) were less likely to receive untreated or inadequately treatment. And that the impact of all these factors (except for the migrants) on treatment status are fully mediated through the syphilis diagnosis time, with the direct effect of migrants that would have resulted in a higher rate of no or inadequate treatment (OR = 2.34, 95% CI: 1.08–5.32) was partially cancelled out by the syphilis diagnosis time.ConclusionsPregnant women who were migrant without local residence and women with syphilis diagnosed at a later gestational age were more likely to slip through the cracks of the existing antenatal care system. More programs should focus on eliminating these gaps of residence-related health inequalities. This research highlights actionable elements for health services interventions that could increase syphilis treatment rates among pregnant women.

A Review on Current Management of Syphilis in Pregnancy: Persistent Risk to The Public's Health

Syphilis is a bacterial sexually transmitted diseases (STI) caused by Treponema pallidum. Due to their high rates of morbidity and mortality, maternal and congenital syphilis are important public health issues in every country. According to the World Health Organization (WHO), there are around 5,6 million new infections worldwide each year, and Syphilis-positive pregnant women have to 80% chance of having a negative pregnancy outcome, such as a stillbirth or spontaneous abortion. Pregnant women typically don't get treated for syphilis at one or more prenatal visits. Because of this, it is necessary to have up to date understanding the effects of syphilis infection on maternal and newborn outcomes, as well as for guidelines for current syphilis treatment and care. Keywords: Syphilis, Pregnancy, current treatment, Sexually transmitted diseases (STI), Treponema pallidum.

HIV Prevalence and Risk Factors Among Young Men Who Have Sex With Men in Southwest China: Cross-sectional Questionnaire Study.

Previous studies showed an increase in HIV prevalence among young men who have sex with men aged 25 years or younger in China. This study aimed to assess HIV prevalence and associated factors among young men who have sex with men in the Guangxi Zhuang Autonomous Region. This study was conducted in 4 cities (Guilin, Liuzhou, Beihai, and Nanning) in the Guangxi Zhuang Autonomous Region between June 2014 and May 2016. Participants were reached through web-based and site recruitment approaches. Laboratory tests were performed to detect HIV and syphilis infections. A self-administered questionnaire was used to collect data from 632 eligible young men who have sex with men. The prevalence of HIV and syphilis was 9.3% (59/632) and 11.4% (72/632), respectively. Multivariable logistic analysis showed that ethnic minority (adjusted odds ratio [AOR] for Han Chinese vs other minorities 0.28, 95% CI 0.11-0.71, P=.007), receptive sexual positioning in the past 6 months (AOR 2.94, 95% CI 1.32-6.53, P=.008), current syphilis infection (AOR for individuals without vs those with infection 0.38, 95% CI 0.19-0.75, P=.005), inconsistent condom use in the past 6 months (AOR 1.91, 95% CI 1.06-3.45, P=.03), and psychotropic drug use before last anal intercourse (AOR 16.70, 95% CI 2.34-119.18, P=.005) were independently associated with HIV infection. There is an urgent need to scale up HIV and syphilis interventions in young men who have sex with men. Some subgroups might need specific attention for HIV prevention, including ethnic minority men, individuals with a history of sexually transmitted infections, and individuals who have been engaging in receptive anal sex.

LB1576. High Prevalence of Oral Treponema pallidum by PCR among US Adults with Early Syphilis

Abstract Background Treponema pallidum (T. pallidum) is transmitted from person to person by direct contact with widespread dissemination early after acquisition. Current syphilis diagnostic testing is limited to darkfield microscopy from visible lesions and serologic antibody detection. T. pallidum molecular diagnostics are urgently needed. Methods As part of a multicenter US syphilis treatment trial that completed enrollment in March 2022 (NCT 3637660), we randomized 249 adults with early syphilis infection to 1 vs 3 weekly doses of benzathine penicillin G to compare treatment response at 6 months. In a small substudy (n=32) presented here, consenting participants at the University of Alabama at Birmingham (UAB) and Emory University had pre-treatment oral (buccal mucosa and posterior pharynx) and lesion swab samples collected. Following DNA extraction, T. pallidum burden in samples was quantified by targeting the tp0574 gene. Syphilis was staged by experienced providers according to physical examination and serology. Results Study participants were men (100%) and most were living with HIV (91%) with mean CD4 count 477 cells/mm3. Syphilis stage was categorized as primary in 6 (19%), secondary in 18 (56%) and early latent in 8 (25%). Oral swab qPCR positivity rates were 17% in primary disease, 44% in secondary disease, and 63% in early latent disease (see Figure). Lesion PCR positivity was similar in primary and secondary syphilis (40% and 38.5%). Mean treponemal burden was highest on oral swabs of participants with early latent syphilis (13,128,969) and lesion swabs of participants with secondary syphilis (2,033,309). Conclusion Among adult males, many living with HIV, data suggest a role for oral and lesion swabs for the molecular detection of T. pallidum. Widespread availability of PCR, the relative ease of oral specimen collection, and the opportunity to directly demonstrate T. pallidum in persons with early latent syphilis suggest the opportunity for PCR testing to enhance and refine syphilis diagnostic testing. The elevated proportion of positive oral samples and significant organism burden in secondary and early latent syphilis is consistent with potential for transmission. Disclosures All Authors: No reported disclosures.

Syphilis in people living with HIV does not account for the syphilis resurgence in Japan

ObjectivesThis study aimed to determine whether the current syphilis resurgence in Japan is attributable to incident syphilis in people living with HIV (PLWH). MethodsThis observational, retrospective, population-based study used data from the Japanese National Database. Data were extracted for PLWH who received antiretroviral treatment between January 2009 and December 2018. Using these data, along with the annual number of PLWH and syphilis diagnoses in the total population of Japan acquired from the National Institute of Infectious Diseases, the fraction of PLWH with syphilis compared to the total number of syphilis patients reported each year was calculated. ResultsThere was a dramatic increase in syphilis cases during the study period. However, the incidence of syphilis in PLWH was stable during 2010–2018; the fraction of PLWH with newly diagnosed syphilis remaining at approximately 2% of the total PLWH cases in Japan each year. The proportion of newly diagnosed syphilis cases in PLWH decreased during the study period and accounted for <10% of the total syphilis cases in Japan since 2016 (14.9% in 2015 to 9.5% in 2016 and 5.9% in 2018). An increasing trend in the number of newly diagnosed syphilis cases in PLWH aged >50 years was observed (7.4% in 2010 to 10.4% in 2014 and 14.9% in 2018). ConclusionsThe recent dramatic increase in syphilis cases in Japan was not seen in PLWH. Thus, the resurgence of syphilis in Japan cannot be attributed to its transmission in the PLWH population.

Characterisation of Treponema pallidum lineages within the contemporary syphilis outbreak in Australia: a genomic epidemiological analysis

The incidence of syphilis has increased markedly in the past decade in high-income countries, including Australia. To date, however, genomic studies of Treponema pallidum have focused mainly on the northern hemisphere. Here, we aimed to characterise the lineages of T pallidum driving the current syphilis epidemic in Australia. In this genomic epidemiological analysis, using phylogenomic and phylodynamic analyses, we analysed 456 high-quality T pallidum genomes collected from clinical samples in Australia between Oct 19, 2005, and Dec 31, 2020, and contextualised this information with publicly available sequence data. We also performed detailed genomic characterisation of putative antimicrobial resistance determinants, in addition to correlating single-locus typing of the TP0548 allele with the T pallidum phylogeny. Phylogenomic analyses identified four major sublineages circulating in Australia and globally, two belonging to the SS14 lineage, and two belonging to the Nichols lineage. Australian sublineages were further delineated into twelve subgroups, with five of the six largest subgroups associated with men who have sex with men, and the sixth lineage was predominantly associated with heterosexual people. Most Australian T pallidum genomes (398 [87%] of 456) were genotypically macrolide resistant, and TP0548 typing correlated significantly with T pallidum genomic subgroups. These findings show that the current syphilis epidemic in Australia is driven by multiple lineages of T pallidum, rather than one distinct outbreak. Major subgroups of T pallidum in Australia have emerged within the past 30 years, are closely related to global lineages, and circulate across different sexual networks. In conjunction with improved testing and treatment, these data could better inform the control of syphilis in Australia. National Health and Medical Research Council, Australian Research Council.

Characteristics of Brain White Matter Microstructure in HIV Male Patients With Primary Syphilis Co-Infection.

Purpose: To investigate the effect of syphilis infection on the microstructure of white matter (WM) in HIV-infected male patients using diffusion tensor imaging (DTI).Methods: Twenty-seven HIV-infected male patients with current syphilis or a history of syphilis (HIV +/syphilis +), twenty-nine HIV-infected male patients without syphilis co-infection (HIV +/syphilis–), and twenty-nine healthy controls (HC) were enrolled. All participants received DTI, and all patients received comprehensive neuropsychological assessment. Tract-based spatial statistics (TBSS) was adopted to analyze the DTI measures: fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). Correlation analysis was conducted to investigate the relationships between DTI measures and cognitive performance.Results: There were no significant differences in DTI measures between HIV+/syphilis– and HC. Compared with HC, lower FA was found in body of corpus callosum (BCC), splenium of corpus callosum (SCC), genu of corpus callosum (GCC), the bilateral anterior corona radiata (ACR), superior corona radiata (SCR), posterior corona radiata (PCR), and posterior thalamic radiation (PTR) in HIV+/syphilis+ (p < 0.05). Higher RD was found in BCC and SCC (p < 0.05). Compared with HIV+/syphilis–, lower scores were found in complex motor skills (CMS) in HIV+/syphilis+, lower FA was found in BCC, SCC, GCC, the bilateral ACR, SCR, PCR, PTR, cingulate gyrus (CGC), the right inferior fronto-occipital fasciculus (IFO), the retrolenticular part of internal capsule (RLIC), sagittal stratum (SS), external capsule (EC) in HIV+/syphilis+ (p < 0.01). Correlation analysis uncorrected for multiple comparisons showed there was a positive correlation between FA in GCC and CMS, FA in BCC, and CMS in HIV+/syphilis+.Conclusions: Syphilis co-infection can have an additive or synergistic effect on the brain WM in HIV-infected subjects. HIV-infected patients without syphilis should be actively treated to avoid syphilis infection.

High Burden of Active Syphilis and Human Immunodeficiency Virus/Syphilis Coinfection Among Men Who Have Sex With Men, Transwomen, and Genderqueer Individuals in Zimbabwe.

Syphilis increases human immunodeficiency virus (HIV) acquisition risk and impacts the immunologic and virologic response among people living with HIV (PLHIV). We assessed the prevalence of active or current syphilis and HIV/syphilis and their correlates among men who have sex with men (MSM), transwomen, and genderqueer (TGW/GQ) individuals in Zimbabwe. Among a respondent-driven sample of MSM and TGW/GQ who were tested for HIV and syphilis in Harare and Bulawayo, Zimbabwe in 2019 (n = 1511), multiple logistic regression was used to assess correlates of active syphilis. Unadjusted logistic regression was used among PLHIV (n = 340) due to small sample size. All analyses were unweighted as data did not reach convergence for HIV. Prevalence of active syphilis overall and among PLHIV was 5.5% and 10.1%, respectively, in Harare, and 5.6% and 11.0%, respectively, in Bulawayo. Participants were more likely to have active syphilis if they were PLHIV (adjusted odds ratio [aOR], 2.2; 95% confidence interval [CI], 1.4-3.6), aged 25-34 years (aOR, 2.2 years; 95% CI, 1.3-3.8 years; reference, 18-24 years), or self-report sexually transmitted infection symptoms (aOR, 1.8; 95% CI, 1.1-3.0). Compared with Bulawayo TGW/GQ, MSM in Harare (aOR, 0.2; 95% CI, 0.1-0.5) and Bulawayo (aOR, 0.2; 95% CI, 0.1-0.4), and TGW/GQ in Harare (aOR, 0.2; 95% CI, 0.1-0.6) were less likely to have active syphilis. Among PLHIV, coinfection was 13.0% among TGW/GQ and 9.7% among MSM. Odds of coinfection were higher for those aged 25 to 34 years (OR, 3.7 years; 95% CI, 1.2-11.1 years) and lower among Harare MSM (OR, 0.2; 95% CI, 0.1-0.7), Bulawayo MSM (OR, 0.1; 95% CI, 0.0-0.4), and Harare TGW/GQ (OR, 0.1; 95% CI, 0.0-0.4) compared with Bulawayo TGW/GQ. Findings highlight a high burden of syphilis among MSM and TGW/GQ and underscore the importance of HIV/syphilis detection and improved service delivery for these groups.

Estimation of benzathine penicillin G demand for congenital syphilis elimination with adoption of dual HIV/syphilis rapid diagnostic tests in eleven high burden countries.

WHO recommends use of rapid dual HIV/syphilis tests for screening pregnant women (PW) during antenatal care to prevent mother-to-child transmission. Scale-up of testing implies a need to accurately forecast and procure benzathine penicillin (BPG) to treat the additionally identified PW with syphilis. Country-reported ANC coverage, PW syphilis screening and treatment coverage values in 2019 were scaled linearly to EMTCT targets by 2030 (constant increasing slope from 2019 figures to 95% in 2030) for 11 focus countries. Antenatal syphilis screening coverage was substituted with HIV screening coverage to estimate potential contribution of rapid dual HIV/syphilis tests in identifying additional PW with syphilis. BPG demand was calculated for 2019-2030 accordingly. The estimated demand for BPG (in 2.4 million unit vials) using current maternal syphilis prevalence and treatment coverage will increase from a baseline of 414,459 doses in 2019 to 683,067 doses (+65%) in 2021 assuming immediate replacement of single HIV test kits with rapid dual HIV/syphilis tests for these 11 countries. Continued scale up of syphilis screening and treatment coverage to reach elimination coverage of 95% will result in an estimated demand increase of 160%, (663,969 doses) from 2019 baseline for a total demand of 1,078,428 BPG doses by 2030. Demand for BPG will increase following adoption of rapid dual HIV/syphilis test kits due to increases in maternal diagnoses of syphilis. To eliminate congenital syphilis, MNCH clinical programs will need to synergize with disease surveillance programs to accurately forecast BPG demand with scale up of antenatal syphilis screening to ensure adequate treatment is available for pregnant women diagnosed with syphilis.

Detection of Treponema pallidum DNA in Oropharyngeal Swabs and Whole Blood for Syphilis Diagnosis.

Syphilis diagnosis relies on serological tests, which may be falsely nonreactive or may be reactive but not reflect current syphilis. Polymerase chain reaction for detection of T. pallidum DNA was performed on 123 oropharyngeal swabs, 120 whole bloods, and 46 lesion exudate swabs from 123 untreated individuals with syphilis (cases); oropharyngeal swabs from 148 at-risk controls without syphilis; and 73 oropharyngeal swabs and 36 whole bloods from 73 individuals recently treated for syphilis. Most (90.2%) cases had early syphilis. T. pallidum DNA was detected in 33 (26.8%) of 123 oropharyngeal swabs, 32 (26.7%) of 120 bloods, and 30 (65.2%) of 46 lesion exudate swabs. T. pallidum DNA was detected in 49 (40.8%) of 120 individuals in whom both oropharyngeal swabs and blood were tested. T. pallidum was more likely to be amplified from oropharyngeal swabs when it was amplified from blood than when it was not (15 of 32 [46.9%] vs. 17 of 88 [19.3%], P = 0.003). For each 2-fold increase in serum rapid plasma reagin titer, the odds of detection of T. pallidum DNA in oropharyngeal swabs increased by 1.44 (95% confidence interval, 1.14-1.82, P = 0.003). T. pallidum DNA was not detected in oropharyngeal samples from controls, but it was detected in 3 (8.3%) of 36 bloods from individuals recently treated for syphilis: 2 at 1 day and 1 at 5 days after initiation of syphilis treatment. Nucleic amplification tests can identify recent T. pallidum infection and may be particularly useful for diagnosis of very early or asymptomatic syphilis.

Estimation of Benzathine Penicillin G Demand for Congenital Syphilis Elimination with Adoption of Dual HIV/Syphilis Rapid Diagnostic Tests in Eleven High Burden Countries

Background: WHO recommends use of rapid dual HIV/syphilis tests for screening pregnant women (PW) during antenatal care to prevent mother-to-child transmission. Scale up of these tests implies a need to accurately forecast and procure benzathine penicillin (BPG) to treat the additionally identified PW with syphilis. Methods: Country-reported antenatal syphilis screening and treatment coverage values in 2019 were scaled up linearly to 95% coverage by 2030 for 11 focus countries. Antenatal syphilis screening coverage was substituted with HIV screening coverage to estimate potential contribution of rapid dual HIV/syphilis tests in identifying additional PW with syphilis. BPG demand was calculated for 2019 through 2030 accordingly. Results: The estimated demand for BPG (in 2.4 million unit vials) using current maternal syphilis prevalence and treatment coverage will increase from a baseline of 414,459 doses in 2019 to 683,067 doses (+65%) in 2021 assuming immediate replacement of single HIV test kits with rapid dual HIV/syphilis tests for these 11 countries. Continued scale up of both syphilis screening and treatment coverage to reach elimination coverage of 95% will result in an estimated demand increase of 160%, (663,969 doses) from 2019 baseline for a total demand of 1,078,428 BPG doses by 2030. Conclusions: Demand for BPG will increase following adoption of rapid dual HIV/syphilis test kits due to increases in maternal diagnoses of syphilis. To eliminate congenital syphilis, country programs will need to synergize with disease surveillance programs to accurately forecast BPG demand with scale up of antenatal syphilis screening to ensure adequate treatment is available for pregnant women diagnosed with syphilis. Funding: This study was made possible by support from the Bill & Melinda Gates Foundation, the Clinton Health Access Initiative, the U.S. Centers for Disease Control and Prevention, Atlanta, USA and the World Health Organization, Geneva, Switzerland Declaration of Interest: None to declare.

Discussing current syphilis case definitions: A proposal for a "probable infectious" case.

Syphilis has increased in recent years, causing difficulties for clinicians and public health practitioners alike. While one issue with the current management of syphilis is that it has both a myriad of presentations and complicated laboratory results, another issue relates to the current case definitions used to define and track syphilis in public health surveillance. One item that is missing is a "probable" case definition, which could help capture the number of likely cases of syphilis that were appropriately treated clinically, but which failed to reach public health case definition based on serologic markers. This approach could produce a more accurate picture of the breadth of syphilis transmission in North America and help better appreciate the groups most affected by syphilis change. We put forward and argue this position herein.

Exploring How Epidemic Context Influences Syphilis Screening Impact: A Mathematical Modeling Study.

The current syphilis epidemic in the United States is concentrated in gay, bisexual, and other men who have sex with men (MSM), but substantial heterosexual transmission is reported in some parts of the country. Using the US states of Louisiana and Massachusetts as case studies, we investigated how epidemic context influences the impact of population screening approaches for syphilis control. We constructed a compartmental metapopulation model parameterized to describe observed patterns of syphilis transmission. We estimated the impact of different approaches to screening, including perfect adherence to current US screening guidelines in MSM. In Louisiana, where syphilis cases are more evenly distributed among MSM and heterosexual populations, we projected that screening according to guidelines would contribute to no change or an increase in syphilis burden, compared with burden with current estimated screening coverage. In Massachusetts, which has a more MSM-focused outbreak, we projected that screening according to guidelines would be as or more effective than current screening coverage in most population groups. Men who have sex with men-focused approaches to screening may be insufficient for control when there is substantial transmission in heterosexual populations. Epidemic characteristics may be useful when identifying at-risk groups for syphilis screening.

Lifetime Burden of Incarceration and Violence, Internalized Homophobia, and HIV/STI Risk Among Black Men Who Have Sex with Men in the HPTN 061 Study.

Black men who have sex with men (BMSM) have disproportionate HIV/STI acquisition risk. Incarceration may increase exposure to violence and exacerbate psychosocial vulnerabilities, including internalized homophobia, which are associated with HIV/STI acquisition risk. Using data from HIV Prevention Trials Network 061 (N = 1553), we estimated adjusted prevalence ratios (APR) and 95% confidence intervals (CIs) for associations between lifetime burden of incarceration and HIV/STI risk outcomes. We measured associations between incarceration and HIV/STI risk outcomes with hypothesized mediators of recent violence victimization and internalized homophobia. Compared to those never incarcerated, those with 3-9 or ≥ 10 incarcerations had approximately 10% higher prevalence of multiple partnerships. Incarceration burden was associated with selling sex (1-2 incarcerations: APR: 1.52, 95% CI 1.14-2.03; 3-9: APR: 1.77, 95% CI 1.35-2.33; ≥ 10: APR: 1.85, 95% CI 1.37-2.51) and buying sex (≥ 10 incarcerations APR: 1.80, 95% CI 1.18-2.75). Compared to never incarcerated, 1-2 incarcerations appeared to be associated with current chlamydia (APR: 1.47, 95% CI 0.98-2.20) and 3-9 incarcerations appeared to be associated with current syphilis (APR: 1.46, 95% CI 0.92-2.30). Incarceration was independently associated with violence, which in turn was a correlate of transactional sex. Longitudinal research is warranted to clarify the role of incarceration in violence and HIV/STI risk in this population.

Syphilis infection among people who use and inject drugs in Cambodia: a cross-sectional study using the respondent-driven sampling method.

This cross-sectional study explored the prevalence and correlates of syphilis infection among people who use and inject drugs (PWUD/PWID) in Cambodia. Data were collected in 2017 from 1,677 PWUD/PWID living in the capital city of Phnom Penh and 11 other major provinces using the respondent-driven sampling method. The SD Bioline HIV/Syphilis Duo test was used to determine human immunodeficiency virus (HIV) and current or past syphilis infection. A multivariable logistic regression analysis was conducted to identify risk factors associated with current or past syphilis infection. The prevalence of current or past syphilis infection was 3.8% (95% confidence interval = 2.4-4.6). After adjustment, current or past syphilis infection remained positively associated with being female, living on the streets, having an average monthly income of US$100-299, having transactional sex in the past three months, and having been to a rehabilitation centre in the past 12 months. Current or past syphilis infection was negatively associated with having attained at least high school level of formal education. The findings indicate vulnerability to syphilis infection among PWUD/PWID in Cambodia, particularly among subpopulations who are more marginalized. Syphilis prevention and control programmes should be systematically integrated into HIV and sexually transmitted infection policy and services in the country.