Using surveillance data to monitor trends in the AIDS epidemic.

Series of incident cases of acquired immunodeficiency syndrome (AIDS) must be adjusted before being used to evaluate trends in AIDS incidence or to estimate the current prevalence of the human immunodeficiency virus (HIV). This paper describes adjustments that account for delays in reporting AIDS cases, the lack of HIV-exposure information for some cases, and future diagnoses of AIDS-defining opportunistic illnesses among persons reported with AIDS under the severe immunosuppression criteria of the 1993 AIDS surveillance case definition. These adjustments are illustrated using AIDS cases reported to March 1996.