While most recent news about the spike in sexually transmitted infections (STIs) has focused on gay and bisexual men, new research is showing an emerging epidemic among cisgender women, but mostly linked to the use of substances like cocaine, methamphetamine, and opioids. Researchers and epidemiologists are beginning to look at this trend. There were several presentations at this year's Conference on Retroviruses and Opportunistic Infections (CROI), held in Seattle last week, that dealt with the issue, and the Centers for Disease Control and Prevention (CDC) released new data last month.
"Sometimes analyses of syphilis in the U.S. are not stratified by gender, and when that happens, there's a disproportionate number of cases among men, and it's difficult to discern whether there are new predictors, or different predictors, of syphilis among women," said Jodie Dionne-Odom, M.D., of the University of Alabama-Birmingham, when presenting her study at CROI.
Dionne-Odom's study looked specifically at syphilis rates among women who are living with HIV. The study reviewed the medical records from the Centers for AIDS Research (CFAR) Network of Integrated Clinical Systems of nearly 4,800 women with HIV who had at least one HIV clinic visit between 2005 and 2016. They reviewed the medical records and patient-reported outcomes of those women every 6 months out from their first recorded visit. Of the 417 women who had tested positive for syphilis, 119 women had 125 episodes of incident syphilis during follow-up care.
In the adjusted model to identify predictors of incident syphilis, a history of injection drug use, a hepatitis C diagnosis, and coming into care more recently were all associated with having syphilis. Black women were also more likely than white women to have contracted syphilis in the study. Unlike other STIs, like gonorrhea and chlamydia, which younger women tend to contract at higher rates, Dionne-Odom noted that age did not impact risk of syphilis in this study.
The study did not determine whether the increased risk for syphilis had to do with changes in behavior (like sex work/transactional sex for drugs) or more sex with higher-risk partners.
Rising Connection Between Syphilis and Substance Use Among All Cisgender Women
But it's not just women living with HIV who seem to be more at risk for syphilis if they have a history of substance use. A Feb. 15, 2019 Morbidity and Mortality Weekly Report (MMWR) article observed that "among women with P&S [primary and secondary] syphilis, increases in methamphetamine use, sex with a person who injects drugs, injection drug use, and heroin use were observed in every region of the United States" from 2013 to 2017. Furthermore, they found that among cisgender women and heterosexual cisgender men reporting primary and secondary syphilis, there were increases in methamphetamine, heroin, and injection drug use and sex with a person who injects drugs over the period studied -- in some cases, the rates of drug use had tripled for women.
"These findings indicate that a substantial percentage of heterosexual syphilis transmission is occurring among persons who use methamphetamine, inject drugs or have sex with persons who inject drugs, or who use heroin, and that heterosexual syphilis and drug use are intersecting epidemics," the MMWR states.
STI Elimination Remains a Challenge
But STI rates are not just increasing among people who use drugs. Another talk given at CROI, by Jeanne M. Marrazzo, M.D., M.P.H., with University of Alabama at Birmingham, reviewed the issues in STI treatment overall and across the globe. She looked at STI prevalence and risk factors, the challenges in growing drug resistance to STIs like gonorrhea without a robust pipeline of new antibiotics, whether we can hope to "get to zero" globally with HIV while we have spiking STI rates, and some structural challenges that make eliminating STIs more elusive, such as antibiotic shortages, partner notification, and the cost of performing three-site testing.
She also discussed what has been observed with the advent of pre-exposure prophylaxis (PrEP) and undetectable equals untransmittable (U=U) in many cities among gay and bisexual men, which has also been marked by a new feeling of sexual freedom and reduced stigma. Marrazzo felt that even with these new advances that have created a paradigm shift for men who have sex with men, the same could not necessarily be said for women.
"For women, also it's very different. STIs in women are much more than inconvenient, for reasons I hope you are aware," she said. "Stigma is highly operative, and I would wager that sexual pleasure and freedom remain a very elusive goal for women across the globe."