Changing patterns of sexual behaviour in the era of highly active antiretroviral therapyElford, JonathanCurrent Opinion in Infectious Diseases: February 2006 - Volume 19 - Issue 1 - p 26–32 doi: 10.1097/01.qco.0000199018.50451.e1 HIV infections and AIDS Abstract Author Information Purpose of review To describe changing patterns of sexual behaviour in the era of highly active antiretroviral therapy among gay/bisexual men in Europe, Canada, USA and Australia. Recent findings While there has been a substantial increase in high-risk sexual behaviour among gay men since 1996, this now appears to be levelling off in some cities. Overall the empirical evidence does not support the suggestion that taking highly active antiretroviral therapy or having an undetectable viral load leads to risky sexual behaviour among people with HIV. Nor can HIV treatment optimism alone explain the recent increase in high-risk sexual behaviour. Since 1996, an increasing number of gay men have begun to use the Internet to look for sexual partners. By serosorting on the Internet, HIV-positive men are more likely to meet online, rather than offline, other HIV-positive men for unprotected sex. While serosorting does not present a risk of HIV transmission to an uninfected person, it does present a risk of other sexually transmitted infections and co-infection with resistant virus for HIV-positive men themselves. This review also explores emerging behaviours such as barebacking and strategic positioning as well as the role of crystal meth and Viagra. Summary The review reminds us of the complexity of human and sexual behaviour. Among gay men, sexual behaviour in the era of highly active antiretroviral therapy has been characterized by risk reduction and stabilization as well as increasing risk. These changing patterns provide a new challenge as well as new opportunities for HIV prevention. City University, London, UK Correspondence to Professor Jonathan Elford, City University, Institute of Health Sciences, St Bartholomew School of Nursing and Midwifery, 24 Chiswell Street, London EC1Y 4TY, UK Tel: +44 20 7040 5702; fax: +44 20 7040 5866; e-mail: firstname.lastname@example.org © 2006 Lippincott Williams & Wilkins, Inc.