A dangerous drug trend called “bluetoothing,” in which people inject themselves with the blood of other drug users to get a cheap high, is contributing to spikes in H.I.V. rates in infection hot spots around the world.
The blood-sharing practice, which is many times riskier than sharing needles, has helped fuel one of the fastest-growing H.I.V. epidemics in Fiji and grown widespread in South Africa, another infection capital, according to public health authorities and researchers.
The idea of sharing drug-laced blood is so unthinkably dangerous that for years, experts have questioned how common it is. But even if relatively few people do it, the practice can spread diseases like H.I.V. and hepatitis so quickly that experts say it requires a strong public health response.
While the scale is hard to quantify, blood sharing has emerged in high-poverty areas in Africa and Asia, driven by tougher policing, spiking prices and falling drug supplies.
“In settings of severe poverty, it’s a cheap method of getting high with a lot of consequences,” said Brian Zanoni, an Emory University professor who has studied drug injecting behaviors in South Africa. “You’re basically getting two doses for the price of one.”
In Fiji, the authorities have identified bluetoothing as one force behind an alarming spiral in H.I.V. rates. The number of new H.I.V. infections rose 10-fold between since 2014 and 2024, according to U.N.AIDS, a United Nations program, and an outbreak was declared there in January.
About half of newly diagnosed people on antiretroviral treatments in Fiji said they contracted H.I.V. by sharing needles, according to 2024 data shared by the U.N. program, though it is unclear how many of them intentionally shared blood, as well. The rise in cases is concentrated among 15-34 year olds.
“We’re seeing young kids dying from H.I.V., children who’ve been involved in drug use and sex,” said Eamonn Murphy, the director of U.N.AIDS regional support teams in the Asia Pacific region, Central Asia and Eastern Europe. Bluetoothing, he said, is one among many factors driving the surge, along with lack of access to clean needles and high levels of unprotected sex.
One reason the practice hasn’t been more widespread is that it delivers a diminished dose of a drug. It isn’t clear how much of a high secondary users receive, and some medical experts say there is no more than a placebo effect.
“It’s not nearly as effective as people were hoping,” said Mr. Murphy, whose U.N. team has helped coordinate Fiji’s health response. “Further down the chain of injecting, there’s much less of a buzz.”
To bluetooth, a first drug user injects a drug like heroin or methamphetamine. Then that person’s drug-infused blood is injected into another user, hoping to get high off the same dose.
In Tanzania, where the practice is sometimes called “flashblooding,” it has spread from the inner city to the suburbs, and women in short-term housing were disproportionately vulnerable. In a South African sample, Mr. Zanoni’s research team found 18 percent of drug injectors had used the blood-sharing method.
Unusual injection practices in Pakistan include selling half-used, blood-infused heroin syringes.
“It’s the same combination of poverty and lack of awareness, as well as cheap drugs being introduced and then the price going up,” said Mr. Murphy. “The real challenge will be dealing with introduction of harm reduction programs” in Fiji, he added, where stigma against drug use remains a significant challenge.
Though small quantities of blood are shared in bluetoothing, combining incompatible blood types risks severe adverse reactions, even if no virus particles are transmitted.
Mr. Zanoni, of Emory, called the practice “underexplored but super high-risk.” Per drop of blood from a person with H.I.V., he said, “there’s tens and thousands of particles you’re being exposed to.”
“It’s the perfect way of spreading H.I.V., “ said Catherine Cook, the executive director of Harm Reduction International, a nonprofit group based in Britain. “It’s a wake-up call for health systems and governments — the speed with which you can end up with a massive spike of infection because of the efficiency of transmission.”