Walgreens pathologists at St. Luke’s International Mater Hospital in Seattle are offering patients a rare test for HIV, selected as an elective component for a trial participants. The results of this early-stage study suggest that Mater has one of the few laboratory-based HIV-prevention products that seems to work in a controlled manner in keeping HIV transmission relatively low.

The early-stage study results, published Feb. 6 in Clinical Infectious Diseases, looked at 17 patients at an HIV level three or greater (the “top” level) of reporting, Boston area Partners clinic infection prevalence, and testing capacity (test/tretinoin ratio ≤25 to 1).

“Among these patients, we found that tretinoin–containing antiretroviral therapy (a regimen of five daily viremia tests) was highly effective in preventing viral reinfection and subrecurrence,” said lead author Carmen Martinez, MD, MPH, chair of the laboratory pathologist and infectious disease physician at St. Luke’s. “It allowed the individual to reduce their risk of receiving HIV infection altogether.”

In the current study, no additional HIV exposure was detected in the participants in the trial.

“The high clinical relevance of this study means we can evaluate the efficacy of the treatment, particularly among patients with HIV at low risk,” said Dr. Martinez. “At this time, physicians should cultivate the impression that tretinoin is a highly effective tool for HIV prevention and that low risk, early exposure to infection is the need to intervene. This goal may also be reinforced by the published data demonstrating success in preventing refococcal and skin infection in HIV-infected individuals.”

As described in a press release, the study was funded by the National Institutes of Health, National Institutes of Health-funded Clinical & Translational Research, and the Sinai Foundation. Additional investigators include Carmen Martinez, Ph.D., and Ronald Yellen, Ph.D.,p