Epidemiology of HIV in the United States and Canada: current status and ongoing challenges.

Purpose: To determine the status of the HIV epidemic in the United States and Canada.

Methods: We used data on AIDS and HIV diagnoses for 1996-2005 reported to the United States and Canadian national surveillance systems to determine trends in AIDS and HIV (33 US states only) diagnoses and to identify population groups most affected by HIV. HIV incidence for Canada was determined using back-calculation methods. We also determined the proportion of persons diagnosed late (HIV diagnosis within 12 months before AIDS diagnosis).

Results: AIDS diagnosis rates were higher in 2005 among blacks (54.1 per 100,000) and Hispanics (18.0) compared with whites (5.9) in the United States and among blacks (4.7) and aboriginal peoples (4.9) compared with whites (0.7) in Canada. Since 2001, HIV diagnoses increased among men who have sex with men in both countries and in Canada, increased among persons from HIV-endemic countries and where heterosexual contact was the only identified risk of transmission. Overall, HIV incidence remained relatively stable in Canada during that period. A large proportion of persons were diagnosed late in the disease process (United States, 54.3%; Canada, 64.2%).

Conclusions: Rates of HIV transmission remain a challenge in both the United States and Canada as overall diagnosis rates have not decreased in recent years. Renewed prevention efforts are needed to further reduce the high HIV diagnosis rates among racial/ethnic minorities and to decrease HIV transmission among men who have sex with men.