CDC Publishes Revised HIV Surveillance Case Definition


The U.S. Centers for Disease Control and Prevention (CDC) has issued a revised surveillance case definition for HIV, published in the April 11, 2014, edition of Morbidity and Mortality Weekly Report. The new definition consolidates prior age-specific definitions into a single set of criteria for all age groups. The revised criteria also take into account improvements in diagnostic tests and a new classification for early infection.

"Laboratory criteria for defining a confirmed case now accommodate new multitest algorithms, including criteria for differentiating between HIV-1 and HIV-2 infection and for recognizing early HIV infection," according to the MMWR report. "A confirmed case can be classified in one of five HIV infection stages (0, 1, 2, 3, or unknown); early infection, recognized by a negative HIV test within 6 months of HIV diagnosis, is classified as stage 0, and acquired immunodeficiency syndrome (AIDS) is classified as stage 3. Criteria for stage 3 have been simplified by eliminating the need to differentiate between definitive and presumptive diagnoses of opportunistic illnesses."

However, they stress, "The surveillance case definition is intended primarily for monitoring the HIV infection burden and planning for prevention and care on a population level, not as a basis for clinical decisions for individual patients."

The addition of stage 0 for early infection takes advantage of more sensitive tests that allows diagnosis of acute or primary HIV infection, which occurs before the antibody response has fully developed. This is important because newly infected individuals often have a high viral load -- and therefore greater likelihood of transmitting the virus to others -- and recent research suggests that very early antiretroviral therapy may enable a cure for some individuals.

Several changes in the revised definition are related to combining the previous adult and pediatric criteria. It eliminates the requirement for evidence that a child's mother has HIV if laboratory testing of the infant can independently confirm infection. Staging of HIV infection is now determined the same way for children aged 6-12 as for adolescents and adults.

The revised list of Stage 3 or AIDS-defining opportunistic illnesses is as follows:



RM Selik, ED Mokotoff, B Branson, et al. Revised Surveillance Case Definition for HIV Infection -- United States, 2014. Morbidity and Mortality Weekly Report 63(RR03):1-10. April 11, 2014.