HIV: Stages of Infection
The U.S. Centers for Disease Control and Prevention (CDC) classify HIV infection into four stages.1
Stages of HIV infection
- Stage 1: There are no AIDS-related conditions AND the CD4+ cell count is greater than 500 or the percent of CD4+ cells is at least 29% of all lymphocytes.
- Stage 2: There are no AIDS-related conditions AND the CD4+ cell count is 200 to 499 or the percent of CD4+ cells is 14% to 28% of all lymphocytes.
- Stage 3: The CD4+ cell count is lower than 200, the percent of CD4+ cells is less than 14% of all lymphocytes, or an AIDS-related condition is present.
- Stage unknown: No information is available on the CD4+ cell count or the presence of AIDS-related conditions.
In general, the higher the CD4+ count, the less likely it is that opportunistic diseases will occur. Most people who have untreated HIV experience a gradual drop in the number of CD4+ cells. Each person responds uniquely to this decline.
Schneider E, et al. (2008). Revised surveillance case definitions for HIV infection among adults, adolescents, and children aged < 18 months and for HIV infection and AIDS among children aged 18 months to < 13 years—United States, 2008. MMWR, 57(RR-10): 1–12. Also available online: http://www.cdc.gov/mmwr/PDF/rr/rr5710.pdf.
|Primary Medical Reviewer||E. Gregory Thompson, MD - Internal Medicine|
|Specialist Medical Reviewer||Peter Shalit, MD, PhD - Internal Medicine|
|Last Revised||April 8, 2010|