Background:  Recent outbreaks of syphilis among men who have sex with men and increasing prevalence of unprotected sex have raised concerns of potential increases in HIV transmission.

Methods:  Using data from 29 states with confidential reporting of HIV/AIDS cases diagnosed during 1999 through 2002, we determined annual diagnosis rates by demographic characteristics, including 10-year birth cohorts (aged 13 years or older at diagnosis), and the annual number of diagnoses by mode of exposure. All analyses were adjusted for reporting delays and unreported mode of exposure. We calculated the estimated annual percentage change (EAPC) and 95% confidence intervals (CI) by fitting an unweighted regression line to the natural logarithm of the rates or counts using calendar year as a regressor variable.

Results:  During 1999 to 2002, 102,590 persons were diagnosed with HIV in the 29 states. Diagnosis rates were higher among males (27.7 per 100,000 in 2002) than females (10.7). The highest rates were observed among blacks (75.6 per 100,000 in 2002), followed by Hispanics (29.3) and whites (8.0). Diagnosis rates increased significantly from 1999 to 2002 among whites (EAPC 2.0, 95% CI 0.3 - 3.8); males born in 1970 or later (2002 rate 44.7, EAPC 10.9, 95% CI 8.7 - 13.2 for males born in the 1970s; 2002 rate 9.9, EAPC  52.5, 95% CI 24.1 - 87.4 for males born in the 1980s); and females born in the 1980s (2002 rate 8.2, EAPC 13.1, 95% CI 6.0 - 20.8). No significant increase was observed among women born in the 1970s. The annual number of HIV diagnoses increased significantly by about 5% per year among men who have sex with men (95% CI 3.9 - 6.6).  Among men who have sex with men, the number of HIV diagnoses increased among white, black, and Hispanic men.

Conclusions:  The increasing numbers of HIV diagnoses during 1999 through 2002 reflect primarily increases in the number of diagnoses among men, particularly men who have sex with men, and increases in the number of diagnoses among persons born in more recent decades. Intervention efforts should continue to ensure access to appropriate care and prevention services for these populations.

Keywords: men who have sex with men; race/ethnicity; surveillance