Tindr and Grindr
An estimated 36.9 million people live with HIV around the world, but thanks to education, prevention efforts, and advances in medicine, the immunodeficiency virus is nowhere near as deadly as it was when U.S. doctors first identified it in 1981. New HIV infections have declined by 35 percent since 2000, and AIDS-related deaths have dropped by 42 percent since the peak in 2004, according to the latest figures from UNAIDS.

But for young people in South Asia, that trend is going in reverse, and researchers are struggling to explain why. Between 2001 and 2014, the number of 10- to 19-year-olds who died from AIDS-related infections nearly quadrupled, from roughly 1,500 to 5,300, according to a report released by UNICEF.

In the Philippines, teens account for almost 10 percent of all people living with HIV, and in a span of just four years, new infections in the country have risen by 50 percent among older teens.

So what’s behind the new spread of infections, which the UNICEF has dubbed a "hidden epidemic"? In its new report about Asia Pacific, the children’s-welfare organization pinpointed one possible explanation: mobile dating apps such as Tinder and Grindr, which have created instant opportunities for "casual spontaneous sex as never before," the report posits.

While that may be true, the theory that dating apps are contributing to the spread of HIV in Asia is not based on hard data. Rather, UNICEF’s report relied on interviews with teens like Nest, an HIV-negative 19-year-old living in Bangkok who said he uses apps like Grindr, Jack’d, and Growlr — unsurprisingly — to meet and date other gay men, and, yes, occasionally to have sex.

"Young gay men tell us that their access to casual sex has increased enormously since the launch of the dating apps, and that sex arranged via apps tends to be spontaneous and more risky," Thailand-based UNICEF spokesperson Andrew Brown said in an email to TakePart. But save for Tinder, which allows users as young as 13, many dating apps, including Grindr, Jack’d, and Growlr, require their users to be over the age of 18—which doesn't explain why AIDS-related deaths are on the rise among 10- to 19-year-olds in Asia Pacific.

Despite the reliance on anecdotal evidence, UNICEF’s claim made headlines all over the world this week. UNICEF HIV/AIDS adviser Wing-Sie Cheng told The Guardian that she was "convinced that there is a link" between dating apps and the epidemic among adolescents in the Asia Pacific region. In an interview with Al Jazeera, the regional adviser's language was even stronger: "The increased availability of mobile apps has fueled the rise [in] infections."

But Brown admitted to TakePart that evidence supporting the theory is not statistical.

"At this stage, we do not have a definitive causal link between the rise of dating apps and the increase in adolescent HIV. This is partly because getting reliable data about at-risk adolescents is difficult, because they are often hidden from traditional surveys," he said.

He offered this clarification: "What we are saying is that the increase in use of mobile dating apps has helped create an enabling environment for risky sexual behavior" — emphasis his — "and could be a contributing factor in new HIV infections."