Research conducted in mice supports a previous petri dish study’s finding that cocaine causes a physiological susceptibility to HIV infection, not necessarily just a behavioral one. Publishing their findings in Scientific Reports, researchers studied how cocaine affects the reaction to injections of HIV among mice genetically engineered to have a human immune system.

“Substance use and abuse is a major issue, especially when it comes to HIV infection,” Dimitrios Vatakis, PhD, an assistant professor of medicine in the division of hematology and oncology at the University of California, Los Angeles, and the study’s senior author, said in a press release. “There has been a general attitude, especially in the scientific but also the general community, that risky behavior is the main reason for higher infections. This study shows that under the same transmission conditions, drug exposure enhances infection through a collective of biological changes.”

The mice were divided into two groups. For five days, one group of mice was injected with saline and the other with 5 milligrams of cocaine per kilogram of weight. Half the mice in each group were then injected with HIV. All mice were then given their daily doses of saline or cocaine for two weeks, after which point the researchers collected blood and tissue samples.

The mice who were injected with cocaine and HIV had higher viral loads than those injected with saline and the virus. Additionally, nine of the 19 mice injected with saline and HIV had undetectable viral loads, compared with three of the 19 mice injected with cocaine and the virus.

The researchers concluded that cocaine likely hampers the immune defense against the virus.

To read the press release, click here.