As the International AIDS Society’s 12th Conference on HIV Science (IAS 2023) drew to a close on Wednesday, continued our conversations about the latest research being presented, with updates on post-exposure prophylaxis for STIs (Doxy PEP), implementation of HIV PrEP, and the effectiveness of U=U.

Miguel Gomez, Director of, spoke with Carl Dieffenbach, PhD, and Louis Shackelford, MPH, about HIV and STI prevention science presented at the conference. Carl is Director of the Division of AIDS at NIH’s National Institute of Allergy and Infectious Diseases (NIAID) and Louis is Acting Director for External Relations at the NIH-supported HIV Vaccine Trials Network (HVTN). First, they discussed insights into the research reported last year about the effectiveness of what has become known as Doxy PEP”—the use of the drug doxycycline as post-exposure prophylaxis for sexually transmitted infections, particularly in the context of condomless sex while taking HIV PrEP. Louis also pointed to the need to tackle stigma and discrimination that contributes to disparities in PrEP use.

Carl and Louis also shared thoughts on their main conference takeaways. Carl reiterated the significance of the REPRIEVE study findings discussed earlier this week. He also noted discussions around the ongoing need to address significant structural, implementation, and messaging challenges to scale up PrEP and PEP everywhere. Louis spoke about presentations on innovative ways to communicate about HIV research. View their conversation below:

Finally, Miguel spoke with Erica Crittendon, MPH, MS, a third-year student at the University of Washington Medical School, and Louis about their conference highlights. Erica discussed her poster presentation about the impact of internalized HIV stigma on care outcomes among a cohort of people with HIV in Durban, South Africa. She found that higher levels of internalized stigma resulted in greater risks of dropping out of care. Louis noted that he was pleased to join many sessions about ways to enhance community engagement in HIV research, noting he had gathered several ideas from other countries that he’ll bring to his work.

Erica shared that another highlight for her was the new World Health Organization (WHO) guidance on HIV viral suppression which reinforces that people with HIV who achieve and maintain an undetectable level of virus by consistent use of antiretroviral therapy do not transmit HIV to their sexual partner(s) and are at low risk of transmitting HIV vertically to their children. The evidence in the WHO guidance further indicates that there is negligible, or almost zero, risk of transmitting HIV when a person has an HIV viral load measurement of less than or equal to 1,000 copies per mL, also commonly referred to as having a suppressed viral load. View their conversation below:

IAS 2023, convening in Brisbane, Australia, features the latest advances in basic, clinical, and operational HIV research and seeks to move science into policy and practice. The conference features seven plenary sessions, more than 60 symposia and oral abstract sessions, hundreds of poster sessions, and many satellite sessions featuring highly diverse and cutting-edge research. Many of the studies that are being presented have been conducted by or funded by federal partners, including NIH, CDC, PEPFAR, DoD, and others.

As is the custom in Australia, acknowledges the Jagera and Turrbal people as the Traditional Custodians of Meanjin (Brisbane), the land on which IAS 2023 is taking place. We pay our respects to Jagera and Turrbal elders past, present, and emerging.

Follow all of our conversations from IAS 2023 this week here on the blog as well as on on’s Facebook, Instagram, and Twitter, and on the LinkedIn account of the HHS Office of Infectious Disease and HIV/AIDS Policy.

This blog post was published by on July 26, 2023.