RCTs of treatment as prevention have shown significant prevention of onward HIV transmission among serodiscordant couples, but observational studies of clinical practice have not consistently replicated these findings. There are particular concerns among men who have sex with men (MSM). In this podcast, Dr. Paul MacPherson explores some of the issues. Dr. MacPherson is a specialist in the Division of Infectious Diseases at the Ottawa Hospital, an associate professor in the Department of Medicine, and the Department of Biochemistry, Microbiology and Immunology at the University of Ottawa, and a clinician scientist at the Ottawa Hospital Research Institute.In their analysis article, Dr. MacPherson and his co-author Patrick O’Byrne examine HIV treatment as prevention in MSM.Full article: https://www.cmaj.ca/lookup/doi/10.1503/cmaj.150605To request a transcript of this podcast, contact cmajgroup@cmaj.ca-----------------------------------Subscribe to CMAJ Podcasts on Apple Podcasts or your favourite podcast app. You can also follow us directly on our SoundCloud page or you can visit www.cmaj.ca/page/multimedia/podcasts.