Researchers have shown an increase in HIV cases in Tijuana among people who inject drugs.

Researchers from the University of California, San Diego School of Medicine have presented data suggesting a new HIV epidemic in Tijuana, Mexico, partly due to unabated ‘drug tourism’ by the border closure internationally due to the COVID-19 pandemic. They found that the rate of HIV incidence among people who use drugs (PWID) in Tijuana had reached an all-time high of 11 per 100 person-years (PA), a statistical time measure that roughly translates to 11% per year.

The HIV incidence rate among San Diego PWIDs who cross the border to buy drugs was found to be lower at 2.77 per 100 PY, but still high compared to the HIV incidence rate among San Diego PWIDs. San Diego who do not cross the border, for whom the HIV incidence rate was zero.

Migration and mobility have long been key drivers of HIV transmission, especially among PWID who are vulnerable to HIV. The San Ysidro Port of Entry, which separates San Diego from Tijuana, is considered the busiest land border crossing in the Western Hemisphere, handling approximately 10 million pedestrians and 15 million vehicles carrying 25 million passengers per year . It is the fourth busiest in the world.

For years, HIV incidence in Tijuana was stable or declining, thanks in part to a multimillion-dollar effort by the Global Fund for HIV, Tuberculosis and Malaria to support needle exchange programs and country needle exchange and other public health measures; but that funding ended in 2013. Some Mexican government funding to community-based organizations providing HIV services to marginalized populations was cut in 2019. The emergence of the COVID-19 pandemic in 2020 diverted more resources from HIV prevention and treatment efforts, an already vulnerable population even more vulnerable.

According to Gudelia Rangel, PhD, co-director of this study and researcher at El Colegio de la Frontera Norte and the US-Mexico Border Health Commission, “It is important to understand that public health issues like this are binational in nature. Viruses don’t stay in one place and we need to work closely with partners on both sides of the border to find the right resources.

The research team includes Britt Skaathun, PhD, assistant professor; Antoine Chaillon, MD, PhD, associate professor; Annick Borquez, PhD, assistant lecturer; Tetyana Vasylyev, PhD, assistant professor; Irina Artamanova; Alicia Harvey-Vera, PhD; Carlos F. Vera and Brendon Woodworth, all at UC San Diego, with Caroline Ignacio, PhD, Columbia University.

The researchers said the findings underscore the urgency of restoring and expanding efforts such as mobile needle-exchange programs and better access to responsive health services providing antiviral therapies and pre-exposure prophylaxis ( PrEP), drugs that significantly reduce the risk of HIV infection for people at high risk.