Can being poor affect the way you respond to HIV treatment? Yes, say researchers from the Harvard School of Public Health. In a recent study, they determined that a person’s socioeconomic position could influence the effectiveness of initial therapy—suggesting that the success of antiretroviral medication isn’t a strictly biological matter.

“In this study, we looked at a social factor to see if it would be a predictor [of] whether or not a patient is going to respond to treatment,” says Dr. Linda Marc, lead author of the study and now a lecturer at the Yale School of Public Health. “Poorer people have more daily hassles—for example, they might not have 50 cents to take the bus—[and] stress is known to influence the immune system.”

Since one or some combination of three traits—income, education and occupation—is generally used to define socioeconomic status, Marc’s group chose to examine the relationship between a person’s educational background and the success of antiretroviral therapy. They examined HIV-positive people who’d never taken meds before; after starting treatment, those with lower education levels reached initial regimen failure sooner than study participants who had college or graduate degrees. Current IV-drug-using subjects, as well as black participants—two groups who statistically may have lower levels of schooling—were also more likely to experience first-regimen failure than others.

Doctors and medical experts need to expand traditional biology-based research to take a closer look at the social factors affecting their patients, recommends Marc, who adds that “the findings support the development of health promotion programs focusing on psychological and behavioral aspects associated with HIV treatments.” Marc also says pharmaceutical companies should consider putting money toward these research areas—and soon.