Dr. Grant believes that clinical and public health practice inspires the best research. His goal is to find ways for people to breath more easily, and to end HIV transmission and disease. His work with HIV started in 1983 with the epidemic when he was a graduate student in epidemiology at UC Berkeley. With the completion of his work pioneering HIV pre-exposure prophylaxis (or PrEP) in 2014, he pivoted to focus on the underpinnings of the epidemic, including stigma, trauma, injustice, addiction, and depression. His current clinical practice is on pulmonary medicine, and how breathing intersects with emotional well being. The next phase of his research focuses on novel transformative interventions for depression and anxiety, including ketamine and MDMA assisted psychotherapies.

Dr. Grant has had a clinical practice in pulmonary and critical care medicine from 1994 to the present, including at Zuckerberg San Francisco General Hospital, San Francisco Veterans Administration Medical Center, and UCSF Health. He started the Sexual Health Improvement Project at UCSF in 2014; this was the first clinical service at UCSF to offer HIV preexposure prophylaxis. He served as the Chief Medical Officer of the San Francisco AIDS Foundation from 2014 to 2018, where he oversaw the initiation of the largest PrEP service in San Francisco, HIV treatment initiation in a sexual health clinic, and HCV treatment linked with a needle exchange site. The SFAF PrEP service is innovative in being rooted in a community based organization, led by nurses, pioneering same day PrEP initiation (and later, same-day HIV treatment initiation), and offering education for non-daily or 2-1-1 PrEP dosing.

Dr. Grant has served as an advisor for laboratory medicine, antiretroviral therapy, and pre-exposure prophylaxis to the CDC, the FDA, and the WHO. He helped develop the WHO recommendation for PrEP (AIDS 2016) and he drafted the WHO PrEP Implementation Tool Kit in consultation with hundreds of experts and stakeholders around the world (https://www.who.int/hiv/pub/prep/prep-implementation-tool/en/). He co-founded a ketamine assisted psychotherapy practice called "Healing Realms" in 2017, and now serves on the board of directors of the American Society of Ketamine Physicians, Psychotherapists, and Practitioners (ASKP). He is a mentor in the California Institute of Integral Studies Certificate Program in Psychedelic Treatment and Research (CIIS CPTR).

Key findings from Dr. Grant's research include the following:

1. Conceptualization and estimation of transmissibility: Dr. Grant developed the concept of transmissibility (now denoted with "beta") and developed a method for estimating transmission of HIV per sexual contact and per sexual partner using epidemiological data (JID 1987). This parameter formed the basis of a generation of mathematical models of infectious epidemics.

2. Diagnostic innovations that guide therapy: Dr. Grant was the first to demonstrate that oral fluid could be used for HIV diagnostic antibody testing (CDLI 1996). He later conducted research that led to the first sequence based assay for drug resistance (or any other condition) to be approved by the FDA (J Clin Micro 2003).

3. High viral load in nonpathogenic SIV infections: Dr. Grant's laboratory discovered a null allele of CCR5 in the natural host of simian immunodeficiency virus. The host genotype was associated with viral load in nonpathogenic infection (Current Biology 1998).

4. Drug resistant HIV has diminished clinical consequences: First case report of transmission of protease inhibitor resistant HIV-1 (NEJM 1998). Finding that primary drug resistance to certain classes of antiretroviral therapy is increasing overtime, and is associated with delayed virological responses to therapy (JAMA 2002). Finding that drug resistant viremia is associated with preserved CD4+ T cell count responses to therapy, suggesting a trade-off for the virus between resistance and virulence (AIDS 1999). Persistent partial CD4+ T cell count responses proved to require continued exposure to therapy that retains partial antiviral activity and maintains selection for viruses with diminished replication capacity (NEJM 2001).

5. Pre-exposure Prophylaxis is safe, effective, and feasible: Dr. Grant's iPrEx trial found that daily oral emtricitabine/tenofovir disoproxil fumarate decreases HIV acquisition among men who have sex with men and transgender women (NEJM 2010). He also conducted the first open label demonstration project of preexposure prophylaxis, showing that adherence is higher when information about safety and efficacy is provided (Lancet ID 2014). He published the first and still largest series of PrEP use among transgender women (Deutsch 2015). He and his colleagues Identified a correlate of protection and a candidate surrogate marker for efficacy of pre-exposure prophylaxis (Anderson 2012).