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HIV: Stages of Infection - Topic Overview

The U.S. Centers for Disease Control and Prevention (CDC) classify HIV infection into 3 stages:1

CDC stages of HIV infection

  • Acute retroviral syndrome: This is an illness with symptoms like mononucleosis. It often develops within a few days of infection with HIV, but it also may occur several weeks after the person is infected. The symptoms can range from mild to severe and usually disappear on their own after 2 to 3 weeks. But many people do not have symptoms or they have such mild symptoms that they don't notice them.
  • Stage 1 (HIV infection): There are no AIDS-related conditions AND the CD4+ cell count is at least 500 cells per microliter or the percent of CD4+ cells is at least 29% of all lymphocytes.
  • Stage 2 (HIV infection): 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 (AIDS): 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.

The World Health Organization (WHO) classifies HIV infection into 4 stages:1

WHO stages of HIV infection

  • Stage 1 (HIV infection): The CD4+ cell count is at least 500 cells per microliter.
  • Stage 2 (HIV infection): The CD4+ cell count is 350 to 499.
  • Stage 3 (advanced HIV disease, or AHD): The CD4+ cell count is 200 to 349.
  • Stage 4 (AIDS): The CD4+ cell count is less than 200 or the percent of CD4+ cells is less than 15% of all lymphocytes.

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.

    This information is produced and provided by the National Cancer Institute (NCI). The information in this topic may have changed since it was written. For the most current information, contact the National Cancer Institute via the Internet web site at http:// cancer .gov or call 1-800-4-CANCER.

    WebMD Medical Reference from Healthwise

    Last Updated: /2, 14 1
    This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
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