The Additive Effect of ART and PrEP in Reducing HIV Incidence in British Columbia, Canada

The slogan “undetectable = untransmittable” encapsulates the principle that risk for sexual transmission of HIV is almost zero when antiretroviral therapy (ART) drives viral load below 1000 copies/mL. In a treatment-as-prevention initiative begun in 2009 in British Columbia, Canada, ART was made available to all people living with HIV (PLWH). New HIV diagnoses then declined — particularly among people who inject drugs, but the decline was slower among gay, bisexual, and other men who have sex with men (MSM). In 2018, British Columbia launched a subsidized PrEP program for gay, bisexual, and other MSM that led to a sharp decrease in HIV incidence.

In a population-based analysis, investigators sought to characterize the effects of free access …