So-called "drug tourism" may be fueling a new HIV outbreak in Tijuana, unabated by the closure of the international border due to the COVID-19 pandemic, UC San Diego School of Medicine researchers announced Friday at the Conference on Retroviruses and Opportunistic Infection.
Specifically, the researchers found that the HIV incidence rate among people who use drugs in Tijuana had risen to an unprecedented 11 per 100 person-years, a statistical time measure that roughly translates to 11% per year. The HIV incidence rate for people using drugs in San Diego who cross the border to purchase drugs was found to be lower, at 2.77 per 100 P-Y but still high compared with the HIV incidence rate among drug users who do not cross the border, for whom the HIV incidence rate was zero.
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"These rising rates occurred during a period when the U.S.-Mexico border was closed to nonessential travel," said Steffanie Strathdee, associate dean of Global Health Sciences, referring to the period between March 2020 and November 2021.
Strathdee said that people are crossing the border, often for extended periods, to get drugs that are cheaper and more accessible.
"Obviously, viruses don't require passports to spread and walls don't keep out infectious disease. We need to bolster HIV prevention efforts on both sides of the border," Strathdee said.
According to researchers, HIV incidence in Tijuana had been stable or declining — in part due to a multimillion-dollar effort by the Global Fund for HIV, Tuberculosis and Malaria to support safe need and syringe exchange programs in the country and other public health measures, but that funding ended in 2013.
Additionally, some Mexican government funding to community-based organizations providing HIV services to marginalized populations was reduced in 2019. The emergence of the COVID-19 pandemic in 2020 diverted more resources away from HIV prevention and treatment efforts, making an already vulnerable population even more vulnerable.
"It's important to understand that public health issues like this are binational in nature, said Gudelia Rangel, co-director of this study and researcher at El Colegio de la Frontera Norte and US-Mexico Border Health Commission. "Viruses don't stay in one place, and we need to work closely with partners on both sides of the border to find adequate resources."
The researchers said the findings underscore the urgency of restoring and expanding efforts such as mobile needle exchange programs and greater access to tailored health services providing antiviral therapies and pre- exposure prophylaxis, medications that significantly reduces the chances of HIV infection for persons at high risk.