Acute HIV infection is the initial stage of HIV, and it lasts until the body has created antibodies against the virus.

Acute HIV infection develops as early as 2 to 4 weeks after someone contracts HIV. It’s also known as primary HIV infection or acute retroviral syndrome. During this initial stage, the virus is multiplying at a rapid rate.

Unlike other viruses, which the body’s immune system can normally fight off, HIV can’t be eliminated by the immune system.

Over a long time, the virus attacks and destroys immune cells, leaving the immune system unable to fight off other diseases and infections. When this happens, it can lead to late stage HIV, known as AIDS or stage 3 HIV.

It’s possible to contract HIV from a person with an acute HIV infection because of the high rate of viral replication during this time.

However, most people with acute HIV infection don’t even know they’ve contracted the virus.

This is because the initial symptoms resolve on their own or may be mistaken for another illness such as the flu. Standard HIV antibody tests aren’t always able to detect this stage of HIV.

Acute HIV infection symptoms are similar to those of the flu and other viral illnesses, so people may not suspect that they’ve contracted HIV.

In fact, the Centers for Disease Control and Prevention (CDC) estimates that of the nearly 1.2 million people in the United States living with HIV, about 14 percent of them don’t know they have the virus. Getting tested is the only way to know.

Symptoms of acute HIV infection can include:

Not all symptoms may be present, and many people with acute HIV infection don’t have any symptoms.

However, if a person does experience symptoms, they may last for a few days or up to 4 weeks, then disappear even without treatment.

Acute HIV infection occurs 2 to 4 weeks after initial exposure to the virus. HIV is transmitted through:

  • contaminated blood transfusions, primarily before 1985
  • sharing syringes or needles with someone living with HIV
  • contact with blood, semen, vaginal fluids, or anal secretions containing HIV
  • pregnancy or breastfeeding if the mother has HIV

HIV isn’t transmitted through casual physical contact, such as hugging, kissing, holding hands, or sharing food utensils.

Saliva doesn’t transmit HIV.

HIV can affect people of any age, sex, race, or sexual orientation. However, behavioral factors may put certain groups at an increased risk for HIV. These include:

If a healthcare provider suspects that a person has HIV, they’ll perform a series of tests to check for the virus.

A standard HIV screening test won’t necessarily detect acute HIV infection.

Antibody test

Many HIV screening tests look for antibodies to HIV rather than the virus itself. Antibodies are proteins that recognize and destroy harmful substances, such as viruses and bacteria.

The presence of certain antibodies usually indicates a current infection. However, it can take several weeks after an initial transmission for HIV antibodies to appear.

If a person’s antibody test results are negative but their healthcare provider believes they may have HIV, they may be given a viral load test too.

The healthcare provider may also have them repeat the antibody test a few weeks later to see if any antibodies have developed.

Other tests

Some tests that may be able to detect signs of acute HIV infection include the:

  • HIV RNA viral load test
  • p24 antigen blood test
  • combined HIV antigen and antibody tests (also called 4th generation tests)

The p24 antigen blood test detects the p24 antigen, a protein that’s only found in people with HIV. An antigen is a foreign substance that causes an immune response in the body.

The 4th generation test is the most sensitive test, but it doesn’t always detect infections within the first 2 weeks.

People who take a 4th generation test or p24 antigen blood test will also need to confirm their HIV status with a viral load test.

Anyone who’s been exposed to HIV and may be experiencing acute HIV infection should get tested right away.

If a healthcare provider knows that someone has had possible recent exposure to HIV, they’ll use one of the tests capable of detecting acute HIV infection.

Proper treatment is crucial for people diagnosed with HIV.

Healthcare providers and scientists agree that early treatment with antiretroviral drugs should be used by all HIV-positive people who are ready to start taking a daily medication.

Early treatment may minimize the virus’s effects on the immune system.

Newer antiretroviral medications are usually very well tolerated, but there’s always the possibility of side effects.

If a person thinks they’re experiencing a side effect of or an allergic reaction to their medication, they should immediately contact their healthcare provider.

In addition to medical treatment, healthcare providers may also suggest certain lifestyle adjustments, including:

There’s no cure for HIV, but treatment allows people with HIV to live long and healthy lives. The outlook is best for people who begin treatment before HIV has damaged their immune system.

Early diagnosis and the right treatment help prevent HIV progressing to AIDS.

Successful treatment improves both the life expectancy and quality of life of someone living with HIV. In most cases, HIV is considered a chronic condition and can be managed long term.

Treatment can also help someone living with HIV reach an undetectable viral load, at which point they’ll be unable to transmit HIV to sexual partners.

Acute HIV infection can be prevented by avoiding exposure to the blood, semen, anal secretions, and vaginal fluid of a person living with HIV.

Below are some ways to reduce the risk of contracting HIV:

  • Reduce exposure before, during, and after sex. A variety of prevention methods are available including condoms (male or female), pre-exposure prophylaxis (PrEP), treatment as prevention (TasP), and post-exposure prophylaxis (PEP).
  • Avoid sharing needles. Never share or reuse needles when injecting drugs or getting a tattoo. Many cities have needle exchange programs that provide sterile needles.
  • Take precautions while handling blood. If handling blood, use latex gloves and other barriers.
  • Get tested for HIV and other STIs. Getting tested is the only way a person can know whether they have HIV or another STI. Those testing positive can then seek treatment that can eventually eliminate their risk of transmitting HIV to their sexual partners. Being tested for and receiving treatment for STIs reduces the risk of transmitting them to a sexual partner. The CDC recommends at least yearly testing for people who inject drugs or who have sex without a condom or other barrier method.

Getting an HIV diagnosis can feel emotionally devastating for some people, so it’s important to find a strong support network to help deal with any resulting stress and anxiety.

There are many organizations and individuals dedicated to supporting people living with HIV, as well as many local and online communities that can offer support.

Speaking with a counselor or joining a support group allows people with HIV to discuss their concerns with others who can relate to what they’re going through.

Hotlines for HIV groups by state can be found at the Health Resources and Services Administration’s website.

Read this article in Spanish.