Mode of Collection:
State and Territorial Health Departments report HIV/AIDS cases to CDC using uniform surveillance case definitions and case report form.
Data include demographic characteristics, living status, mode of exposure to HIV, case definition category, and other clinical information.
All 50 states, the District of Columbia, U.S., dependencies and possessions, and independent nations in free association with the United States report HIV/AIDS data to CDC.
The HIV/AIDS surveillance activities employed by most reporting areas include four major reporting sources: hospitals, physicians, public and private clinics, and medical records systems (death certificates, tumor registries, etc.). Using a standard confidential case report, the health departments collect information and transmit it to CDC electronically, without personal identifiers. Estimated data on HIV infection and AIDS are adjusted using a maximum likelihood statistical procedure that accounts for the differences in reporting delays among various characteristics (demographic, vital status, etc.). HIV/AIDS surveillance data are provisional and are updated annually.
Response Rates and Sample Size:
Although completeness of reporting differs by geographic region and patient population, studies conducted by state and local health departments indicate that the reporting of AIDS cases in most areas is more than 85 %complete.
The case definitions of HIV infection and AIDS have been modified several times since 1985. To assess trends in AIDS cases, deaths, and prevalence, it is preferable to use case definitions adjusted for reporting delays and presented by year of diagnosis, rather than counts by year of report.