After about 2 to 4 weeks of exposure to HIV, a person may have rashes and flu-like symptoms. After this, there may be no symptoms for several years until the effects of immune system damage appear.

HIV is a virus that targets the immune system. In 2022, around 1.2 million people in the United States were living with HIV, but many are not aware of their status, partly due to a lack of symptoms. Researchers estimate that 13% of people above 13 years in the US with HIV do not know they have it.

If a person develops symptoms, the symptoms may initially seem like the flu, mild, or attributed to another illness. The virus may present with headaches, fever, muscle aches, and rashes, or symptoms can be undetectable.

This article looks at the different stages of HIV, its symptoms and transmission, and possible treatments.

HIV is a virus that targets the body’s immune system. The virus damages and destroys white blood cells called CD4 T cells, which usually help the body fight off infections from:

Without treatment, HIV keeps replicating and damages more and moreTrusted Source cells, ultimately weakening the immune system and leaving it unable to fight these infections.

However, a treatment known as antiretroviral therapy can reduce the amount of HIV in the blood to very low levels.

When viral levels are low enough to be undetectable, HIV no longer damages the immune system. At this point, there is virtually no risk of transmitting it to others. In short, undetectable = untransmittable (U=U)Trusted Source.

Learn more about HIV.

The symptoms experienced by a person living with HIV depend on the body’s stage of infection. Not all individuals will see their condition progress at the same rate or display the same symptoms.

If left untreated, an HIV infection typically goes through three stagesTrusted Source:

Some people do not experience symptoms for years or until their condition is very advanced. As a result, people cannot rely on symptoms to tell if they have contracted HIV. The only way to know is by taking a test.

Anyone with possible exposure to HIV should speak with a healthcare professional. Information on testing for HIV in the U.S. is available here.

Stage 1: Acute HIV infection

About 2 to 4 weeksTrusted Source after HIV enters the body, it can show up as symptoms that last for days or weeks.

During this period, people may experience:

This is the seroconversion period. Seroconversion is the body producing antibodies against HIV. This is the body’s natural response to detecting an infection.

In this phase, there tends to be a large amount of HIV in the blood. It replicates rapidly, so the risk of transmitting the virus to others is high.

Not everyone develops symptoms at this stage. Others experience mild flu-like symptoms that largely go unnoticed. This means that people can contract HIV without knowing it, which makes testingTrusted Source very important.

If a person thinks HIV exposure is possible, it is important to consult with a healthcare professional for advice and to ask them about a preventive medication called postexposure prophylaxis (PEP).

Healthcare professionals can order tests to check for HIV. Some tests can detect the virus after 10 daysTrusted Source, while others detect it after 90 days exposure. People may need to take more than one test to get accurate results.

Stage 2: Chronic HIV infection

In this second phase, HIV is still reproducing at very low levels within the body, and it continues to damage immune cells. People typically do not experience symptoms or get sick from the virus during this stage.

This stage is also known as asymptomatic HIV infection or “clinical latency.”

Without medication, the chronic stage of an HIV infection can last for a decade or more. People can still transmit the virus to others during this time.

Antiretroviral therapy slows or stops the progression of HIV. People who take antiretroviral drugs as prescribed may remain in the chronic HIV stage for life and never develop stage 3 HIV.

Stage 3: HIV

Stage 3 HIV, also known as AIDS, is the most advanced stage of infection. This occurs when a person’s immune system is badly damaged and can no longer fight off new infections.

People who take antiretroviral therapy can maintain a low viral load and may never develop stage 3 HIV. Other factors that affect whether this stage occurs include:

  • age
  • genetic predisposition
  • the strain of the virus

Symptoms of stage 3 HIV can include:

  • weight loss
  • night sweats
  • fever
  • chronic diarrhea
  • a persistent cough
  • skin problems
  • mouth problems
  • opportunistic infections
  • serious illness such as end stage organ dysfunction

A healthcare professional may diagnose stage 3 HIV if a person’s CD4 blood count drops below 200 cells per cubic milliliter (cells/mm3)Trusted Source or if they develop an opportunistic infection.

Opportunistic infections are those that take advantage of a weakened immune system. Common opportunistic infections in the U.S. include:

Without treatment, people with stage 3 HIV typically survive an average of three yearsTrusted Source. With treatment, people can recover from serious HIV-related infections and diseases and bring HIV to a manageable level.

Some symptoms differ by the sex assigned at birth.

The most common ways people acquire HIV are through anal or vaginal sex or sharing drug injection equipment, such as needles, syringes, or cookers.

A person can contract HIV if certain fluids that contain the virus come into contact with damaged tissue or mucous membranes in the genitals, rectum, or mouth.

Is HIV contagious?

Only certain body fluids can pass HIV between people. These fluids includeTrusted Source:

  • blood
  • semen or pre-seminal fluid
  • vaginal fluid
  • rectal fluid
  • breast milk

A baby can contract HIV from a person during pregnancy, childbirth, or nursing. This is less commonTrusted Source.

There are many myths about HIV transmission. People do not contract HIV from any of the following:

  • mosquito bites, ticks, or other insects
  • sweat, tears, or saliva
  • hugging, shaking hands, or social kissing
  • sharing bathrooms, food, drinks, or dishes
  • sexual activities, such as touching that do not involve the exchange of body fluids
  • through the air

The only way a person can know their HIV status is by taking a test. The Centers for Disease Control and Prevention (CDC) recommends that everyone ages 13 to 64Trusted Source should have a HIV test at least once.

There are three types of tests for HIV:

  • Nucleic acid test: This blood test looks for the viral particles, particularly genetic material, in the blood and can reveal a person’s viral load. It involves drawing blood from a vein.
  • Antigen/antibody test: This blood test looks for the presence of antigens or antibodies in the blood, which can signal an HIV infection. It involves either drawing blood or taking a finger prick.
  • Antibody test: This test looks for HIV antibodies in blood or oral fluid. This can involve drawing blood from a vein (for faster detection), taking a finger prick, or using an oral swab.

People can get an HIV test in a healthcare clinic or do a self-test at home.

It is not possible to detect HIV immediately after infection. The time between exposure and when a test can produce accurate results is the “window period.” This can take 10 to 90 daysTrusted Source, depending on the individual and the specific test used.

To ensure an accurate result, a person must take an HIV test after their window period.

A person should talk with a healthcare professional as soon as possible if there is exposure to HIV within 72 hours and ask about postexposure prophylaxis (PEP), which can be highly effective.

There are many ways HIV-negative people can avoid contracting the virus, and there are many ways that HIV-positive people can avoid transmitting it.

Ways to prevent HIV transfer includeTrusted Source the following:

  • Using condoms or other barrier methods correctly when having sex can reduce the risk of transmission.
  • Never sharing needles, syringes, or other drug-injection equipment can help prevent transmission. If a person does share equipment, disinfecting the equipment with bleach can reduce the risk of HIV and hepatitis. The CDC provides advice about cleaning syringes hereTrusted Source.
  • People who are more likely to contract HIV can take preexposure prophylaxis (PrEP). When taken as prescribed, these medications are highly effective at preventing virus transmission. Truvada and Descovy are two oral PrEP drugs approved by the Food and Drug Administration (FDA). The FDA has also approved ApretudeTrusted Source, an injectable PrEP drug which a healthcare professional administers every 2 months.

People who are HIV-positive can prevent transmitting the virus to others by taking antiretroviral drugs.

Most people who use antiretroviral drugs can get the virus to undetectable levels within 6 monthsTrusted Source. Once their viral load is undetectable, there is virtually no risk of transmitting the virus to other people.

PrEP should be available to anyone at risk of HIV infection. A person will need negative HIV testing before initiation of PrEP, and continued lab monitoring and comprehensive HIV and STI prevention planning are also recommended. 2021 guidelinesTrusted Source recommend that doctors should inform all sexually active people about PrEP for the prevention of HIV infection.

Furthermore, anyone who has been sexually active in the last 6 months and meets at least one of the below criteria can receive PrEP:

  • has an HIV-positive partner
  • inconsistent condom use with a partner
  • has had a sexually transmitted infection (STI) within the last 6 months
  • uses injection drugs and shares equipment, or has a partner who participates in injection drug use

What are the first warning signs of HIV?

The first signs of HIV may include swollen lymph nodes, fever, headache, muscle aches, and sores around the body.

How long can a person have HIV without knowing?

Although most people with HIV experience flu-like symptoms in the first few weeks, it may not cause any symptoms for several years.

HIV is a virus that gradually weakens the immune system by targeting CD4 cells. The signs and symptoms differ depending on the body’s stage of infection.

People can live with HIV for many years without displaying any symptoms. This is why getting tested for HIV is so important.

With effective treatment, many people living with HIV can enjoy long, healthy lives.