HIV infection progresses at varying rates and may never progress to the final stage of acquired immune deficiency syndrome (AIDS). Table 1 lists the stages of infection and the characteristics associated with each stage.
Table 1. Stages of Infection. | Stage | Duration | Clinical Symptoms | Characteristics |
| Acute HIV Infection (AHI) | Generally occurs within 2-4 weeks after infection. It lasts until the body has developed a concentration of antibodies that can be detected by laboratory assays. | Influenza-like symptoms will occur in some people and can include fever, headache, and rash. Treatment with anti-retroviral therapy (ART) at this stage can result in significant benefits. | High levels of viremia greatly increases the risk of transmission during the acute stage.
Transient depression in CD4 T lymphocytes. Elevation of CD8 T lymphocytes. |
| Chronic Phase | This stage can be called chronic, asymptomatic, or clinical latency. Without treatment, HIV infections generally progress to full AIDS in ten years or more. Individuals being treated with ART can remain in this stage for several decades. | Most people are asymptomatic during this stage yet individuals are still able to transmit the virus unless treated with ART and laboratory assays determine an undetected viral load. | HIV replication establishes a steady state and virus levels in plasma reach a "set point" (the viral load that the body settles at within a few weeks to months after HIV infection). CD4 T lymphocyte counts slowly decline. |
| Acquired Immunodeficiency Virus Syndrome (AIDS) | AIDS is the final, most severe stage of HIV infection. The immune system has been compromised to the degree that the body cannot fight off opportunistic infections and are at risk of various forms of cancer. Untreated people with AIDS generally only survive about three years. | Symptoms will vary dependent on the secondary conditions that occur due to the damaged immune system. | AIDS is diagnosed when the CD4 lymphocyte count is <200 cells/µL or if they have certain opportunistic infections. Patients will have a high viral load and can easily transmit to others. |
