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HIV: Stages of Infection


Topic Overview

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.

Related Information

References

Citations

  1. 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.

Credits

ByHealthwise Staff
Primary Medical ReviewerE. Gregory Thompson, MD - Internal Medicine
Specialist Medical ReviewerPeter Shalit, MD, PhD - Internal Medicine
Last RevisedApril 8, 2010

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