Despite prevention efforts, some groups of people are affected by HIV/AIDS, viral hepatitis, STDs, and TB more than other people. The occurrence of these diseases at greater levels among certain population groups than in others is often referred to as a health disparity. A health disparity is the difference that separates a group of interest from a reference group for an indicator of health that is measured in terms of rate, proportion, mean, or some other quantitative measure. Differences may occur by gender, race or ethnicity, education or income, disability, geographic location or sexual orientation. Poverty, unequal access to health care, lack of education, stigma,and racism are linked to health disparities. CDC works in collaboration with state health departments to monitor occurrence of disease and to track disparities in HIV/AIDS, viral hepatitis, STDs and TB in the United States.

Data reported to CDC demonstrates that some population groups continue to be disproportionately affected by HIV/AIDS, viral hepatitis, STDs, and TB. HIV/AIDS and sexually transmitted diseases disproportionately affect men who have sex with men (MSM), blacks and Hispanics. TB is more prevalent among foreign-born persons and US-born blacks. Rates of hepatitis B remain highest among non-Hispanic blacks. Rates of hepatitis C continue to occur in adult age groups, with injection drug use as the most commonly identified risk factor for hepatitis C infection.