Stanford researchers have determined that a preventative medication for HIV could be a cost-effective investment for men at high risk of contracting the virus.

The drug under evaluation was tenofovir-emtricitabine, which a 2010 study found could reduce an individual’s chances of contracting the virus by between 44 and 73 percent, according to an article from the Stanford School of Medicine.

The study, which focused on an economic model for treating men who have sex with other men, or MSM, found that a technique called pre-exposure prophylaxis (PrEP), which entails medicating an entire population daily, could prove economically efficient. According to the U.S. Centers for Disease Control and Prevention, MSM patients comprise more than half of the new HIV infection in the United States each year.

The treatment, however, is still an expensive undertaking. Targeting only the high risk in the MSM population, the treatment would cost $85 billion, according to the study. Previous economic studies have even returned conflicting results by making fewer assumptions. The Stanford study, for example, assumed that patients would stop the medication after 20 years.

“Even though it provides good value, it is still very expensive,” said Jessie Juusola, primary author of the study and Ph.D. candidate in management science and engineering. “In the current health care climate, PrEP’s costs may become prohibitive, especially given the other competing priorities for HIV resources, such as providing treatment for infected individuals.”

Still, the study shows that even at a 20 percent adoption rate among high-risk individuals, the PrEP treatment could prevent 41,000 HIV infections over 20 years.

-Matt Bettonville