Stages of HIV Infection

HIV infection progresses through three stages. Learn about each stage and how treatment affects progression.

Key Points

HIV infection progresses through three stages without treatment.
Antiretroviral therapy (ART) can prevent progression to later stages.
With treatment, most people with HIV never develop AIDS.
CD4 count and viral load are key measures of HIV disease progression.

HIV progresses through three stages. The speed of progression varies from person to person and depends on many factors, including whether a person is receiving HIV treatment. According to the CDC, with proper treatment, people with HIV can stay healthy for many years and may never progress to Stage 3 (AIDS).

Stage 1: Acute HIV Infection

CD4 Count

Normal (500–1,500 cells/mm³)

Viral Load

Very high

Duration

2–4 weeks after infection

Within 2 to 4 weeks after infection with HIV, about two-thirds of people will have a flu-like illness. This is the body's natural response to HIV infection.
During this stage, HIV multiplies rapidly and spreads throughout the body. The virus attacks and destroys CD4 cells (T cells), a type of immune cell.
People in this stage are very infectious because the amount of HIV in the blood (viral load) is very high.
HIV may not show up on some tests at this stage. A nucleic acid test (NAT) can detect HIV the soonest after exposure.

Stage 2: Chronic HIV Infection

CD4 Count

Declining (200–500 cells/mm³)

Viral Load

Lower than Stage 1, but still present

Duration

10 years or more without treatment

In this stage, HIV is still active but reproduces at very low levels. People may not have any symptoms or get sick during this time.
This stage is also called asymptomatic HIV infection or clinical latency. HIV is still transmissible during this stage, even without symptoms.
Without HIV treatment, this period can last a decade or longer, but some people progress through this phase faster.
People who take HIV medicine (ART) as prescribed may be in this stage for several decades and may never move to Stage 3.

Stage 3: AIDS (Acquired Immunodeficiency Syndrome)

CD4 Count

Below 200 cells/mm³

Viral Load

Very high

Duration

Without treatment, survival is typically 3 years

AIDS is the most severe stage of HIV infection. People with AIDS have such badly damaged immune systems that they get an increasing number of severe illnesses, called opportunistic infections.
AIDS is defined as having a CD4 cell count below 200 cells/mm³, or having certain opportunistic infections regardless of CD4 count.
Common opportunistic infections include Pneumocystis pneumonia (PCP), Toxoplasma encephalitis, Cytomegalovirus (CMV), and Mycobacterium avium complex (MAC).
Without treatment, people with AIDS typically survive about 3 years. With effective ART, people can recover from AIDS, though some immune damage may be permanent.

The Role of ART in Preventing Progression

Antiretroviral therapy (ART) is the use of HIV medicines to treat HIV infection. ART is recommended for all people with HIV, regardless of CD4 count. ART reduces the amount of HIV in the blood (viral load) to an undetectable level, which protects the immune system and prevents transmission. Learn more about HIV treatment basics from NIH AIDSinfo.

The Role of ART in Preventing Progression