A new Canadian guideline outlines how new biomedical strategies to prevent HIV infection can best be used in high-risk populations both before and after exposure to the virus. The guideline, published in CMAJ (Canadian Medical Association Journal), applies to adults at risk of HIV infection through sexual activity or injection drug use.

"The large financial cost of HIV infection and the young age of those newly diagnosed (most new cases occur in those aged 30 to 39 years) underscore the economic and social importance of preventing new infections," writes Dr. Darrell Tan, an infectious diseases physician and researcher at St. Michael's Hospital, Toronto, Ontario, with coauthors.

Key strategies, in line with international guidelines, include pre-exposure prophylaxis (PrEP), which refers to the regular use of anti-HIV medications beginning before an exposure occurs, and nonoccupational postexposure prophylaxis (nPEP), which involves taking a course of antiretroviral medications after a sexual or drug use-related exposure to HIV.

The guideline, with easy-reference boxes outlining practical advice for prevention, is aimed at clinicians in primary care, infectious diseases, emergency medicine, nursing, pharmacy and other disciplines. Policy-makers may also find it useful in setting health care policy. The Biomedical HIV Prevention Working Group of the CIHR Canadian HIV Trials Network developed the guideline with a panel of 24 experts from diverse disciplines.

More than half (54%) of all new infections in Canada occur in gay, bisexual and other men who have sex with men, a group with an estimated risk of infection 131 times higher than other men. Injection drug users are estimated to be 59 times more likely than nonusers to acquire HIV. People from countries with endemic HIV are 6.4 times more likely to become infected, and Indigenous people are also at higher risk (2.7 times), compared with the general population in Canada. Read more via Science Daily