How Public Health Can Stem the STI Epidemic

STI Self-Testing at Home

Transportation and embarrassment. Charlotte Gaydos realized during her research in the 1990s that those two factors were preventing many young people from being tested for STIs at clinics. When Gaydos, DrPH ’93, MPH ’89, professor emerita in Infectious Diseases at the Johns Hopkins School of Medicine and in Epidemiology at the Bloomberg School, asked them about self-testing, many were not only open to it but enthusiastic about the idea.

Public health and regulatory authorities such as the Maryland Department of Health and the FDA weren’t sure that participants could correctly use a cotton swab on their genitals, anus, or mouth to collect a sample, or that the specimen would survive transport in the post.

“But women said, ‘Okay, we know where our vaginas are. We use tampons,’” Gaydos says.

After years of work, Gaydos launched I Want the Kit (IWTK) in 2004, offering self-tests for syphilis, chlamydia, and gonorrhea for Baltimore residents. Gaydos would send anyone in the city a free STI self-testing kit on request. After swabbing themselves, recipients could drop the specimen in a postage-paid envelope and send it to a clinical lab. The lab would test it and report positive results to local health departments.

IWTK sent out less than 100 kits the first year—but word quickly spread as IWTK became available to everyone in Maryland and Washington, DC. Currently, the kits are available everywhere from Alaska and Idaho to Oklahoma, Arizona, and several tribal nations.

The project became even more popular during the pandemic. “The number of kits we sent out increased exponentially during COVID-19,” Gaydos says, jumping from 175 kits per month to 615 kits. “People like to be in charge of their own health.”

Studying the Oral Cancer-HPV Link

STIs can cause not only immediate symptoms but more complex health concerns years down the line. For those infected by the human papillomavirus, the appearance of warts on the genitals, anus, or throat and mouth (the oropharynx) can presage cancer years or decades later. In some parts of the U.S., according to a 2022 study by Epidemiology Professor Gypsyamber D’Souza, 9 out of 10 oropharyngeal tumors are caused by HPV. Despite this, oral sex is often perceived as “safer” than vaginal or anal sex.

“Our behaviors are influenced by our perception of risk,” says D’Souza, PhD ’07, MPH, MS. “So while oral sex is very common, protected oral sex is very rare.”

While studies have seen an increase in HPV-caused cancers in all populations, research has shown that older white males are most at risk for developing oropharyngeal cancer. Scientists know little about why men seem to be at higher risk or how to improve early diagnosis.

It’s why D’Souza helped launch the MOUTH (Men Offering Understanding of Throat HPV) Study at the Sidney Kimmel Comprehensive Cancer Center. The team just finished enrolling 1,325 at-risk individuals, including 1,000 men over age 30 who have performed oral sex on two or more partners, and several hundred others with either a history of anogenital precancer or spouses of those with an HPV-related cancer. They are now looking for biomarkers from blood, urine, and throat cells that can identify men most at risk for oropharyngeal cancer, whether these markers can lead to earlier tumor detection, and what treatments can be offered.

“The goal is not to change people’s behavior. It’s to help people make informed decisions, understanding the choices they make and the risks involved with those choices,” D’Souza says. “Cancer risk is not on everyone’s radar.”

Spreading STI Prevention Through Social Networks

Although sex may have evolved as a physical act intimately connected to the survival of the species, it’s also a profoundly social experience, says Carl Latkin, PhD, vice chair of Health, Behavior and Society. Our sex partners are often already part of our social network—and Latkin’s work has revealed that it’s not just infections themselves that are contagious: Behaviors and attitudes about sex, STIs, and prevention also move through social networks.

“People tend to hang out with people who are similar to them, and network members influence each other,” he says. “So networks influence what’s acceptable behavior and what might be risky behavior.”

An effective strategy to spread public health messaging, he found, was to encourage those individuals identified as leaders within the Baltimore community of people who inject drugs to talk about safer sex and not sharing syringes. More recently, Latkin’s work with migrant workers who inject drugs showed that training individuals to talk to their peers about syringe sharing and condom use led to a sustained and significant reduction of 30% to 60% in syringe sharing, buying sex, and sex without a condom.

“We need to move away from individual blame,” he says. “Instead of saying all you need to do is wear a condom, public health needs to consider interventions that look at the social environment, too.

“We need to work with individuals and their networks to promote behavior change,” Latkin says.

Providing STI Care Where It's Needed

As an adolescent medicine fellow at Johns Hopkins Hospital, Errol Fields initially believed that focusing on individual risk factors such as condom usage and number of partners could help reduce the disproportionate rates of STIs among young Black men who have sex with men. His research, however, revealed that individual change couldn’t make a dent in the structural issues such as poverty, racism, and homophobia that were driving STIs.

“If you look at the Baltimore City map, the historic redlined districts from the 1930s and ’40s are the same places where today there’s higher HIV burden, higher poverty, more violence, and lower educational attainment,” says Fields, MD, PhD ’09, MPH, an assistant professor of Pediatrics at the School of Medicine and in Health, Behavior and Society at the Bloomberg School.

Although he saw plenty of patients in clinical settings, he knew that there were many more MSM going untested and untreated. To reach them, he turned to online sites and dating apps many MSM used to find partners. Fields asked these men what interfered with their ability to get treatment.

Many clinics only had 9-5 hours, requiring time off work, the men said. Transportation was often an issue, as was the possibility that they would be recognized in the waiting room. The men reported other barriers, too, such as clinic staff who exhibited biases toward the LGBTQ population and anti-Black attitudes of some health care providers.

A mobile van was the perfect strategy for outreach, testing, and treatment—and Fields wanted to place it where it would have the most impact. Using de-identified user information from the apps, Fields and a team of nurses and outreach workers trained in anti-racist and LGBTQ+ appropriate care parked the van in areas with high virus transmission and a high congregation of MSM on dating apps. In 14 months, the van served more than 150 MSM, most of whom were at very high risk of HIV.

Empowering Sex Workers With Testing, Treatment, and Options

Long before the surge in opiate overdose deaths catapulted the idea of harm reduction into mainstream dialogue on drug use and addiction, Susan Sherman, PhD ’00, MPH, a Bloomberg Professor of American Health in Health, Behavior and Society, was using the approach with Baltimore’s sex workers. By talking to the women, she found that one of their top concerns was STIs. In many clinics, however, their occupations and infections were seen as the result of poor choices.

“These aren’t symptoms of people’s bad behaviors. It’s the result of a bad environment,” Sherman says.

To address these needs, Sherman meets sex workers where they are—literally and metaphorically. Like Fields, Sherman uses a mobile van to provide health services to sex workers and people who use drugs. She also has a harm reduction drop-in center in Southwest Baltimore called SPARC that provides everything from Narcan and wound care to emergency contraception and STI testing and treatment, which helps around 160 women and nonbinary people each week.

What these individuals need, Sherman says, isn’t people telling them what to do but giving them better tools and options to make their own choices. That includes providing sexual health services, as well as emotional support, connection with treatment, clean syringes, and fentanyl test strips. By making small changes to people’s environments to create more autonomy, public health can build healthier communities.

“It really goes from the micro to the macro to make meaningful changes,” she says.