In 2015, health officials in Rhode Island released data showing a dramatic spike in cases of syphilis (79 percent), gonorrhea (30 percent), and HIV (33 percent) in the previous year. The uptick, they said, wasn’t an outlier — it was part of a national trend. And while some of the new cases could be attributed to better testing, officials for the first time said STD rates were rising because of certain high-risk behaviors, including using online dating sites “to arrange casual and often anonymous sexual encounters.”

Since then, the trend for several STDs nationwide has only gotten worse: According to a September report from the Centers for Disease Control and Prevention, there were more than 2 million cases of chlamydia, gonorrhea, and syphilis reported in the United States in 2016 — the highest cumulative number ever recorded. “Not only are we at an all-time high,” Gail Bolan, the director of the division of STD prevention at the CDC, told me, “but we’re starting to see increases in all kind of communities.”

There are a few reasons cases of chlamydia, gonorrhea, and syphilis are on the rise. For instance, epidemiologists have documented a rise in sex without condoms among men who have sex with men.

But health experts increasingly view apps and sites such as Tinder, Grindr, and OkCupid as enablers of high-risk sex, helping people meet and hook up more efficiently than ever before. The impact of these sites is so profound they are also transforming the way health officials track and prevent outbreaks.

“We used to think about what we can do with bathhouses and sex clubs to make sure people’s risk was reduced,” said Dan Wohlfeiler, director of Building Healthy Online Communities, a public health group that works with apps to support STI prevention. These places, after all, had become important meeting points for men who have sex with men — the group most affected by the HIV epidemic.

Today, the public health focus has shifted to what some have called “digital bathhouses.”

“Now that dating sites and apps have become so common, we know we need to work with them,” Wohlfeiler said.

There’s just one problem: Many of the major dating networks don’t want to be involved in STD prevention, nor have they acknowledged the impact they’re having on public health.

“They are hesitant to support sexual health,” said Jeffrey Klausner, a professor of medicine and STD researcher at UCLA. “They realize that their sites could be stigmatized for being associated with STDs. They do as little as possible.”

Just as ride-hailing apps like Uber and Lyft have disrupted transportation — and required new regulations and cultural adaptations — dating sites have disrupted the way people have sex. Health advocates say it’s time they acknowledge that impact — and begin to help fight the STDs they may be helping to spread.

STD outbreaks are being linked to dating apps

Health officials in states around the country have linked recent STD outbreaks to the rise in internet dating.

In one study looking at the link between Craigslist personal ads and HIV, researchers at the University of Minnesota identified an increase in HIV cases in 33 states between 1999 and 2008 — and determined that the advent of Craigslist alone contributed to a 16 percent increase in cases.

In Nevada, a record number of syphilis cases last year was attributed, in part, to the “rise in anonymous sex via social media.” In California, Klausner said, the state health department is increasingly hearing that people with STDs met their partners on sites like Grindr.

“There’s no doubt meeting new partners is much easier with apps,” Wohlfeiler added. “In Wyoming there are still no gay bars, but the internet makes it much easier for people to find each other.”

But the data we have only demonstrates a correlation between online dating and STDs — not causation. Some of the best research on the sex lives of dating app users suggests they tend to have more sexual partners than non-app users. That means people who are drawn to apps may just be more sexually active than non-users, said lead study author Justin Lehmiller, a sex and psychology researcher with Ball State University.

“It may not be that the technology is increasing the risk, but rather there’s this selection effect for people who are more sexually active who tend to use the apps,” he explained. In other words, what matters more than the apps themselves may be the behavior of people who use them. Either way, dating apps and sites appear to be helping facilitate connections — and disease outbreaks — that may not have otherwise happened.

Public health officials are shifting their focus to apps — but apps don’t want to be associated with STDs

As health experts learn more about the links between high-risk behavior enabled by dating apps and STD outbreaks, they’re finding that apps make the work of tracking cases harder to do.

In particular, according to John Auerbach, president and CEO of the public health nonprofit the Trust for America’s Health, the anonymous encounters happening via apps make it harder to do contact tracing, a key epidemiological process in understanding an outbreak.

In the past, when a person was diagnosed with a serious STD, a public health official would call or meet with his or her sexual partners to talk about getting tested and on potential treatment.

But with more anonymous sexual encounters, epidemiologists may not be able to track down people’s partners and notify them that they might have an STD, Auerbach said. And that means any diseases those partners might have can spread more easily too.

An even bigger issue, said Michael Weinstein, the president of the AIDS Healthcare Foundation, is that apps have also changed the modes of disease transmission in sexual networks, making it easier for infections to spread.

“Because these are closed pools of people in limited geographies [using dating apps], it means that infections can spread more easily,” he said. “That’s why we call apps a ‘digital bathhouse.’”

That’s also why public health officials are so eager to work with apps, to get them to add warnings and sexual health messages where users are convening — on the apps themselves.

The big dating apps could be doing much more on the sexual health front

In the UK, the National Health Service is pushing major networks like Tinder and Grindr to advertise places that provide free (or affordable) condoms because of the role they’re playing the rise of sexually transmitted diseases among young men who have sex with men.

When it comes to the US, the much bigger sites like Tinder and Grindr — which have some 50 million and 10 million users, respectively — aren’t doing enough, according to health advocates. “I don’t think they feel it’s their responsibility," Weinstein said.

He and others would like to see online networks engaged in data collection on STDs, partner notification, condom promotion, and distributing information about self-testing and STDs. “If you’re going to hook up, protect yourself and your partner ... making that hip and cool is something the apps could help with a great deal,” said Weinstein.

His group, the AIDS Healthcare Foundation, has put up billboards and bus ads showing silhouettes of people kissing with the names of dating apps (Tinder and Grindr) and STDs, in the hopes of sending the message that encounters originating online can lead to infections.

Tinder responded with a cease-and-desist order, but settled with the foundation in January 2016 after agreeing to add a health safety section to its website. Other major sites, such as OkCupid, also have health information posted to their sites. (Tinder declined to comment on this story, and only pointed me to its website’s “dating safely” advice section.)

They should be doing more, Klausner said, and yet there’s currently no way to regulate them to do so. “From their perspective, [apps] don’t want to be associated with STDs. No one has any authority to require or mandate that these sites do anything to mitigate the consequences of their businesses,” he added. And there isn’t “much political will or leadership to take that on.”

A number of apps and sites have been moving ahead of the major dating networks in working to promote safer sex. The gay men’s social network Hornet allows users to indicate their HIV status in their profiles, choosing from among five options: negative, negative on PrEP (the pill to prevent HIV), positive, positive undetectable, and don’t know.

Hornet also built in a public health intervention: If a user choses negative, he’s asked to disclose the date of his last STD test, and Hornet then reminds users to get tested in six months.

The effort came out of conversations with users about the desire to disclose their status in this context, and avoid awkward and difficult conversations later, said Hornet’s senior health innovation strategist, Alex Garner. “We’ve found it be effective in terms of allowing gay men to express their HIV status in a way that’s empowering and works to combat stigma.”

Daddyhunt, another gay men’s dating site, worked with Wohlfeiler’s Building Healthy Online Communities to create five public service announcements about PrEP, STD testing, and condoms that pop up when users are online. The announcements got more than 2 million views.

[Update: After publication of this story, Grindr sent a statement about their recent effort to add HIV status and “last test date” as standard fields on their profiles, as well as links to sexual health resources, and public service announcements about PrEP.]

There are also dating sites entirely focused on connecting people with STDs. Positive Singles calls itself the “largest confidential herpes and STD” dating network, and Wohlfeiler is working with the University of Washington to develop “partner notification” services, which apps could integrate to let users alert their partners when they have been diagnosed with an STD.

A few people in the health community have made their own efforts to engage users around sexual health issues on Grindr. Antón Castellanos Usigli, a public health professional in New York, created a Grindr profile to connect with at-risk patients about STD prevention services at a Brooklyn clinic. According to the Guardian, within a year he was able to bring in more than 100 new patients for STD testing or counseling — after completely failing to attract anyone through more traditional means of outreach in nightclubs.

Public health researchers in Los Angeles bought ad space on Grindr to advertise ordering self-testing HIV kits.

“We saw that users on Grindr were receptive to receiving information on HIV testing, and they thought HIV self-tests were an acceptable way of getting tested,” said the study’s lead author, Lina Rosengren, an infectious diseases doctor. “So I think [apps] will have an increasing role in public health.”