Generalized Treatment as Prevention Plus Focused Pre-Exposure Prophylaxis Is the Key to Controlling HIV/AIDS

Treatment as Prevention (TasP) and Pre-Exposure Prophylaxis (PrEP) are both widely recognized as essential biomedical tools to control HIV/AIDS. TasP calls for the immediate initiation of fully subsidized and supported antiretroviral therapy (ART) following HIV diagnosis. TasP effectively prevents progression to AIDS, and premature AIDS-related deaths among people living with HIV (PLWH), and simultaneously renders HIV non-transmissible, thus preventing onward HIV transmission. In addition, PrEP has proven effective against HIV transmission among high-risk individuals who are adherent to the regimen. PrEP traditionally consists of two antiretrovirals given orally as one pill daily: originally, tenofovir-DF plus emtricitabine (TDF-FTC), and later, tenofovir-AF (TAF) plus FTC (more recently, other options have become available, including long-acting parenteral formulations; however, these are still of limited availability). Over the last two decades, the province of British Columbia has rolled out TasP among all PLWH, and starting in 2018, PrEP was added as a strategy to reach individuals most at risk of acquiring HIV to further accelerate progress in addressing HIV/AIDS as a public health threat. Our "generalized TasP + focused PrEP" program proved to be synergistic (or multiplicative) as it relates to reducing the HIV effective reproduction number (Re). TasP lowers HIV incidence by reducing the pool of individuals able to transmit HIV, which is dependent on the extent of community plasma viral load (pVL) suppression. Meanwhile, PrEP reduces the number of potential new infections among those most susceptible to acquiring HIV in the community, independent of viral load suppression among PLWH. Our results strongly support widespread implementation of the combination of "generalized TasP + focused PrEP" strategy and underscore the importance of long-term monitoring of Re at a programmatic level to identify opportunities for optimizing TasP and PrEP programs. This approach aligns with the United Nations goal of "Ending HIV/AIDS as a pandemic by 2030", both in Canada and globally.