Researchers around the world are working to develop new ways to stop a collection of diseases that infect more than a million people every day. These infections cause serious, sometimes fatal complications including maternal and infant mortality, infertility or anogenital cancer, and can increase susceptibility to HIV. Billions of people are at risk…but too often these diseases are either ignored, or regarded as unavoidable “facts of life.”
I am describing the devastating global impact of sexually transmitted infections, or STIs. The name covers a collection of bacterial infections such as syphilis, gonorrhea and chlamydia, which, while curable, often go untreated, as well as viral infections such as herpes simplex (HSV), hepatitis B, human papillomavirus (HPV) and HIV, which can be treated but are incurable. The World Health Organization estimates that there are half a billion new infections of curable STIs each year, and that incurable viral STIs are even more prevalent. And late last year, the Centers for Disease Control and Prevention’s 2014 STD Surveillance Report indicated that cases of chlamydia, gonorrhea, and syphilis have risen in the United States for the first time since 2006.
In wealthy countries, a syphilis, gonorrhea or chlamydia infection means a trip to the doctor and a relatively quick course of antibiotics. Incurable STIs such as HPV, HSV or HIV will require a lifetime of expensive, and sometimes invasive, treatment. But for hundreds of millions of women, men and adolescents, whose access to STI screening and treatment is limited due to cost, stigma or misinformation, the consequences of STIs can include infertility, cancer and increased risk for HIV. Women and adolescent girls are impacted disproportionately, while other marginalized populations, such as men who have sex with men and transgender individuals, are also at high risk for acquiring, and suffering the effects of, an STI.
One of the most important things we’ve learned from decades of global research in sexual and reproductive health is that for many young, sexually active people, preventing unintended pregnancy is likely to be a more immediate concern than preventing STIs. Developing a new generation of products that can prevent STIs and unintended pregnancy at the same time could be a major step forward in the effort to control STIs worldwide.
Of course, the world already has a product that is highly effective at preventing both pregnancy and many STIs – the condom. But condoms are only effective if they are used every time you have sex, and we know that low condom use in many places points to another major obstacle to STI prevention: people are reluctant to use a product that they believe will interfere with sexual intimacy or pleasure. People want STI prevention products that are convenient, or perhaps, even enhance sexual pleasure, as in the case of lubricants, to prevent STIs. And women, in particular, need STI prevention they can control.
With the wants and needs of the public in mind, Population Council researchers are working to develop STI prevention products that are more effective, easier to use and more responsive to real life needs and desires. Among the Council’s products currently in clinical and pre-clinical testing are a number of products designed to address multiple sexual and reproductive health needs in a single product. These so-called multipurpose prevention technologies, or MPTs, combine multiple agents to achieve results that are suited to the needs of individual consumers.
The Council’s gels in development could be applied, just like a lubricant, topically to the vagina or rectum at the time of sex, and their slow-release intravaginal rings (IVRs) could provide women with protection for months at a time. The formulations contain different combinations of compounds including zinc acetate, an antiviral agent with activity against HIV and HSV; carrageenan, a seaweed-derived compound active against HPV; griffithsin, a naturally-occurring algae protein designed to prevent HIV, HSV, and possibly other STIs; MIV-150, an antiretroviral drug that protects against HIV infection; and hormonal contraceptives for pregnancy prevention.
The number of promising candidates currently undergoing testing offers the potential to develop multiple products that can respond to peoples’ needs for protection, control, pleasure and convenience. And the fact that several compounds being studied, such as carrageenan, griffithsin and zinc acetate, are not antiviral drugs means that the STI prevention products that contain them may ultimately be available over-the-counter, potentially increasing access, decreasing stigma and reducing cost.
As a new generation of STI prevention products enters development, new ways of thinking about STI prevention may also be taking hold. I am proud to serve as chair of the Population Council’s Microbicides Advisory Board, to help guide forward-looking strategy on STI reduction and the efforts of the Population Council and others to develop new tools that more effectively and conveniently address people’s sexual and reproductive health needs.
Ian McGowan M.D., Ph.D., F.R.C.P. is a professor of medicine in the division of gastroenterology, hepatology and nutrition with a joint appointment in the department of obstetrics, gynecology and reproductive sciences at the University of Pittsburgh School of Medicine. Dr. McGowan is principal investigator of the University of Pittsburgh-based Microbicide Trials Network (MTN), an HIV/AIDS clinical trials network established in 2006 by the U.S. National Institutes of Health (NIH). He serves as chair of the Population Council’s Microbicides Advisory Board.