AIDS

AIDS cases are reported to CDC by all 50 states, the District of Columbia, US dependencies and possessions, and independent nations in free association with the United States¹ using a uniform case definition and surveillance case report form. Cases in this supplemental report were reported according to the 1993 expanded surveillance case definition (MMWR 1992; 41[RR-17:1-190]). A case may be reported upon the initial diagnosis of AIDS (or HIV in states with HIV case surveillance) and later updated when the disease or the vital status changes. Some cases may be first reported at death, either from surveillance activities at a hospital or other places where death may occur or from a review of death certificates or a death registry.

Data in this report include persons diagnosed with AIDS through the end of 2001 and reported to CDC through June 30, 2002. Estimates of persons living with AIDS were derived by subtracting the estimated cumulative number of deaths of persons with AIDS from the estimated cumulative number of persons with AIDS. Estimated AIDS cases and deaths have been adjusted for delays in reporting, but not for incomplete reporting². Annual estimates are given for the most recent year for which reliable estimates are available.

HIV

As of December 2002, 34 states, American Samoa, Guam, the Northern Mariana Islands, and the US Virgin Islands conduct name-based HIV infection case surveillance and report cases to CDC. The data in this report are from the 25 states that began HIV infection case surveillance before 1995. We limit our report to persons reported from these states to best ensure that the majority of persons with HIV in these states have been captured by the system, including both new and previous diagnoses of HIV infection. Data are reported by state or metropolitan area of residence at HIV diagnosis. The estimates of persons living with HIV include persons reported with an HIV diagnosis who have not developed AIDS and whose residence is one of the 25 HIV reporting states at the time of HIV diagnosis. Estimates of persons living with HIV, but not AIDS, were derived by subtracting the estimated cumulative “departures” from HIV (deaths of persons with HIV or persons migrating to AIDS) from the estimated cumulative number of persons diagnosed with HIV

Exposure categories

For surveillance purposes, HIV infection cases and AIDS cases are counted only once in a hierarchy of exposure categories. Persons with more than one reported mode of exposure to HIV are classified in the exposure category listed first in the hierarchy, except for men with a history of both sexual contact with other men and injection drug use. They make up a separate exposure category.

“Men who have sex with men” (MSM) cases include men who report sexual contact with other men and with both men and women. “Heterosexual contact” cases are in persons who report heterosexual contact with someone with HIV or at increased risk for HIV infection. “Other adult” cases include those exposed to HIV through blood transfusions or the receipt of blood products, because of their hemophilia, adults with perinatally acquired HIV infection, confirmed exposure to HIV in health care, laboratory, or household settings, and those for whom the exposure to HIV is not identified. Persons listed under “Pediatric” include children who were under 13 years of age at diagnosis.

Because recently reported AIDS cases are more likely to be reported without exposure information, we statistically adjust the exposure category data based on historical patterns of risk redistribution after follow-up investigations. The adjustment of cases reported without risk information is based on sex-, race-, and region-specific exposure category redistribution of cases reported from 1992 through 1999 that were initially assigned to the “risk not identified” category but subsequently reclassified.

Data presentation

Data are presented by state of residence at diagnosis of HIV or AIDS and by metropolitan area of residence for metropolitan statistical areas with over 500,000 population. Aggregate data are presented for smaller metropolitan statistical areas and nonmetropolitan areas. Age-group data are based on a person’s calculated age as of December 2001. Totals include persons reported without sex, age at diagnosis, race/ethnicity, or exposure category data. Persons reported with an unknown state of residence were excluded from this report.

¹ Included among the dependencies, possessions, and independent nations are Puerto Rico, the US Virgin Islands, Guam, American Samoa, the Republic of Palau, the Republic of the Marshall Islands, the Commonwealth of the Northern Mariana Islands, and the Federated States of Micronesia.

² Karon JM, Devine OJ, Morgan WM. Predicting AIDS incidence by extrapolating recent trends. In: Castillo-Chavez C, ed. Mathematical and Statistical Approaches to AIDS Epidemiology (Lecture Notes in Biomathematics). Berlin: Springer-Verlag; 1989:58-88.