Syphilis in men who have sex with men: advancing research and human rights
Authors: Carlos F Cáceres, Kelika A Konda, Jeffrey D Klausner
Journal: The Lancet Global Health (2021)

At the 69th World Health Assembly in 2016, a commitment was made to reduce syphilis incidence by 90% between 2018 and 2030. The comprehensive meta-analysis by Motoyuki Tsuboi and colleagues in the Lancet Global Health1Tsuboi M Evans J Davies EP et al.Prevalence of syphilis among men who have sex with men: a global systematic review and meta-analysis from 2000–20.Lancet Glob Health. 2021; (published online July 8.)https://doi.org/10.1016/S2214-109X(21)00221-7Summary Full Text Full Text PDF PubMed Scopus (5) Google Scholar on the prevalence of syphilis among men who have sex with men (MSM) worldwide provides a much needed estimate of the burden of disease in this population, and a baseline from which to measure any potential success. The data available for this kind of analysis are clearly limited: meta-analyses miss unpublished studies; there are a variety of potential issues in the use of different tests to detect syphilis and how these tests are interpreted resulting in potential misclassification of cases. Sampling is mostly snowball or convenience-based; and groups with distinct risk profiles are often subsumed within the generic MSM label (eg, male sex workers and transgender women, who are a separate group from a human rights perspective). Clearly, syphilis prevalence is unacceptably high among MSM, 15–20 times higher than in the general male population. Moreover, prevalence seems to be increasing in various regions, including in Europe and North America, Latin America and the Caribbean, and Oceania. This situation seems, in part, indicative of lower access to health services among MSM—a global occurrence that is more common in low-income and middle-income countries. This increase might also reflect the decrease in condom use among MSM observed over the past 20 years,2Aghaizu A Wayal S Nardone A et al.Sexual behaviours, HIV testing, and the proportion of men at risk of transmitting and acquiring HIV in London, UK, 2000–13: a serial cross-sectional study.Lancet HIV. 2016; 3: e431-e440Summary Full Text Full Text PDF PubMed Scopus (34) Google Scholar, 3Hess KL Crepaz N Rose C Purcell D Paz-Bailey G Trends in sexual behavior among men who have sex with men (MSM) in high-income countries, 1990–2013: a systematic review.AIDS Behav. 2017; 21: 2811-2834Crossref PubMed Scopus (47) Google Scholar which in turn indicates a cultural change in this group: the emergence of effective antiretroviral therapy and then of pre-exposure prophylaxis (PrEP) might have increased the acceptability of new sexual adjuvants (eg, new apps and party drugs) that led to increased exposure, especially in North America and Europe. Of particular concern is the situation in Latin America and the Caribbean, where prevalence of syphilis in MSM is consistently more than 10%,1Tsuboi M Evans J Davies EP et al.Prevalence of syphilis among men who have sex with men: a global systematic review and meta-analysis from 2000–20.Lancet Glob Health. 2021; (published online July 8.)https://doi.org/10.1016/S2214-109X(21)00221-7Summary Full Text Full Text PDF PubMed Scopus (5) Google Scholar and where assimilation of the evolving cultural values of North America is quick, but access to sexually transmitted infection (STI) screening and clinical services is limited. Two seemingly counterintuitive findings may be explained thusly: syphilis rates were lowest in low-income countries (compared to those of higher-income levels) and in countries that criminalise homosexual activity. While one potential explanation is underestimation (ie, due to weak surveillance systems, or the unwillingness of MSM to self-identify as such), it is also possible that economic limitations or legal restrictions make exposure too infrequent to maintain syphilis transmission. Of course, these findings should not suggest public health policies—poverty and limitations on human rights are unacceptable and have additional health consequences. To achieve the desired 90% reduction in syphilis incidence among MSM requires several concrete lines of action. First, full integration of biobehavioural STI prevention and control programmes with HIV prevention, together with improved diagnostic technologies including the availability of point-of-care tests. Second, identification of new options in syphilis treatment (given frequent shortages in penicillin supplies); expansion of post-exposure prophylaxis and PrEP; and vaccine development. Third, continued investment in eliminating homophobia and the criminalisation of homosexuality (which are societal structures that put MSM at increased risk by limiting access to preventive and clinical services, and countries' investment in such services). Our own research and programmatic work and that of others over the past 20 years have contributed to these goals through integrating STI and HIV programmes at the city level,4Buchacz KA Siller JE Bandy DW et al.HIV and syphilis testing among men who have sex with men attending sex clubs and adult bookstores—San Francisco, 2003.J Acquir Immune Defic Syndr. 2004; 37: 1324-1326Crossref PubMed Scopus (8) Google Scholar, 5Klausner JD Stanley H Stansell J STD screening among HIV-infected patients in care, San Francisco.AIDS Patient Care STDS. 2001; 15: 73-76Crossref PubMed Scopus (20) Google Scholar ensuring HIV testing activities include STI screening,6Medina-Marino A Glockner K Grew E et al.The role of trust and health literacy in nurse-delivered point-of-care STI testing for pregnant women living with HIV, Tshwane District, South Africa.BMC Public Health. 2020; 20: 577Crossref PubMed Scopus (1) Google Scholar evaluating and implementing dual HIV and syphilis rapid point-of-care tests,7Bristow CC Leon SR Huang E et al.Field evaluation of a dual rapid immunodiagnostic test for HIV and syphilis infection in Peru.Sex Transm Dis. 2016; 43: 57-60Crossref PubMed Scopus (15) Google Scholar, 8Bristow CC Leon SR Ramos LB et al.Laboratory evaluation of a dual rapid immunodiagnostic test for HIV and syphilis infection.J Clin Microbiol. 2015; 53: 311-313Crossref PubMed Scopus (15) Google Scholar demonstrating the potential efficacy of doxycycline prophylaxis for syphilis,9Bolan RK Beymer MR Weiss RE Flynn RP Leibowitz AA Klausner JD Doxycycline prophylaxis to reduce incident syphilis among HIV-infected men who have sex with men who continue to engage in high-risk sex: a randomized, controlled pilot study.Sex Transm Dis. 2015; 42: 98-103Crossref PubMed Scopus (69) Google Scholar and working to identify correlates of immunity in syphilis as a pathway to vaccine development.10Kojima N Bristow CC Maecker H et al.Similarities in the markers of inflammation between men with syphilis and women with increased risk of HIV acquisition.Clin Infect Dis. 2016; 62: 265-266Crossref PubMed Scopus (8) Google Scholar Addressing and reversing structural factors that allow the exclusion of sexually diverse men is certainly difficult; however, through peer-based prevention programmes that empower community members, and through analyses that demonstrate the benefits of sexual inclusion, policy makers and researchers have come together to overcome sexuality-focused stigma and human rights violations. Ultimately, control of infectious diseases like syphilis might not be feasible without an effective vaccine. Dramatic successes were seen in control of syphilis without a vaccine, such as the rapid decline from over 10% to less than 1% in the USA general population in the late 1940s, which was achieved via extensive case-finding and early treatment. However, highly resource-intensive public health programmes are unlikely for syphilis. A vaccine could provide population-wide protection but requires focused research for development. Moving forward, sexual health advocates must continue to collaborate, demand greater research and clinical investment, and hold policy makers accountable. Clearly, sustained political will is necessary to prevent and control syphilis in the long term. JDK reports consulting fees from Danaher, Cepheid, Talis Bio, Curative, Abbott, GSK, Roche, Chembio, and SpeedX. CFC and KAK declare no competing interests. Prevalence of syphilis among men who have sex with men: a global systematic review and meta-analysis from 2000–20Unacceptably high syphilis prevalence among MSM warrants urgent action. Full-Text PDF Open Access