Acute retroviral syndrome (ARS) is the initial, acute stage of an HIV infection. ARS symptoms, which resemble influenza symptoms, appear within several weeks of exposure to the virus and usually last from a few days to a few weeks.

HIV is a virus that affects the immune system and progresses through three stages.

After exposure to HIV, a person may develop various symptoms that resemble those of influenza, or the flu. These symptoms indicate the first stage of HIV infection, which is called ARS.

During the initial, acute phase of HIV infection, the virus levels are high because the individual’s immune system cannot yet mount a response and fight the infection.

Some individuals with ARS are asymptomatic or experience only mild symptoms. Therefore, if an individual thinks that they have come into contact with HIV, they should seek medical advice immediately even if they have no symptoms.

If an individual tests positive for HIV, they can begin highly effective treatment. Modern HIV medicines allow people to have a near-normal life expectancy.

This article explores ARS in more detail. It looks at the timeline of HIV infections, potential symptoms, and when people should seek medical advice.

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When someone contracts HIV, they experience different infection stages.

ARS, or acute HIV infection, is the first of these stages. It happens as the body begins to mount a natural immune response against the infection.

The symptoms of ARS are similar to those of the flu — such as fever, headaches, and body aches — and they may disappear on their own with no treatment.

Currently, there is no cure for HIV, although there are medications that can help individuals living with HIV remain healthy.

ARS begins about 2–6 weeks following transmission of HIV.

Not everyone with HIV will have ARS symptoms. These occur in 25–90% of people who have recently contracted the virus.

Even though ARS symptoms disappear or may not be present in some cases, it is essential to remember that the person is still HIV-positive and that the infection can pass from them to others.

In the early stage of HIV infection, an individual will have extremely high viral levels, making transmission more likely.

Some research has shown that the acute phase of HIV infections accounts for up to 50% of disease transmission.

ARS symptoms often resemble those of the flu or other viral infections, although some individuals have no symptoms at all.

Up to 75% of people will not experience ARS symptoms.

Those who do may have the following symptoms, which can last for several weeks:

  • fever
  • fatigue
  • mouth ulcers
  • skin rash
  • muscle and joint pain
  • unintentional weight loss
  • headaches
  • enlarged lymph nodes
  • sore throat
  • diarrhea

These symptoms are nonspecific, which means that other infections and illnesses can also cause them.

However, if a person has had exposure to HIV and has these symptoms, they should have an HIV test as soon as they can.

According to the Centers for Disease Control and Prevention (CDC), ARS symptoms may last for between a few days and several weeks.

At this point, viral replication slows down, and many people start to feel better as the immune system gradually controls the HIV infection.

One symptom that may persist is lymphadenopathy, or swollen lymph nodes. This painful swelling of the lymph nodes may last for 3 months or longer.

Persistent generalized lymphadenopathy (PGL) is a common finding in people living with HIV infection.

HIV is a progressive disease, meaning that for most individuals living with HIV, their health deteriorates over time.

Someone in the early stages of HIV may have no symptoms at all or only mild symptoms.

However, as HIV advances, it causes increasing damage to the immune system, and the individual will likely develop more severe symptoms.

For this reason, it is vital to recognize symptoms that could indicate an HIV infection.

The sooner a person understands their HIV status, the earlier they can begin medications that can extend their life and keep them healthy.

When HIV first appeared in the 1980s, there was no antiretroviral therapy (ART), and people with the virus had an average life expectancy of just 1–2 years after the diagnosis.

However, today, advances in medicine mean that many people living with HIV have a near-normal life expectancy.

Understanding HIV status is also critical in preventing the transmission of the virus to others.

HIV infection naturally progresses through three stages.

However, it is important to note that if an individual receives treatment, this progression can slow down or stop altogether.

HIV treatment has now advanced to the extent that HIV does not progress to stage 3 in most people.

Stage 1: ARS

This early stage occurs several weeks after contracting the virus.

  • Someone with the infection has high levels of HIV in their body, and the chance of transmission is high.
  • The natural immune response to the HIV infection causes flu-like symptoms in some individuals.
  • Some infected people may have no symptoms or only very mild symptoms.
  • If someone has ARS symptoms and thinks that they may have had exposure to HIV, they should seek medical advice and testing.
  • The person will need an antigen/antibody test or nucleic acid test to confirm acute infection.

Stage 2: Chronic HIV infection

At this stage, the infection becomes chronic rather than acute.

  • Doctors may call this stage asymptomatic HIV infection or clinical latency.
  • The HIV remains active, but the virus does not reproduce quickly.
  • Some individuals have no symptoms during this stage.
  • If an individual takes HIV medication, this stage may last for a decade or longer, although it can progress more quickly in some cases.
  • HIV can transmit to other people during this stage, unless the person with HIV has been taking antiretroviral therapy for at least 6 months and has an undetectable viral load.
  • At the end of this stage, the HIV levels in the blood increase, and immune cells called CD4 cells decrease.
  • As the virus increases, and the immune system gradually fails, the condition progresses to stage 3.
  • In some people, especially those who take HIV medicine as prescribed, HIV will not progress to stage 3.

Stage 3: AIDS

AIDS is the most severe phase of HIV infection.

  • A person with AIDS has an extensively damaged immune system that cannot protect them from pathogens or germs. As a result, they develop severe illnesses.
  • People with AIDS may have extremely high levels of HIV in the blood, and there is a strong possibility of transmission.
  • Without treatment, a person with AIDS typically lives for about 3 years.

The outlook for individuals living with HIV has improved significantly since the disease first emerged.

For instance, research shows that the life expectancy for those receiving supportive medication has increased significantly since 1996. At that time, the expected number of remaining life years for a 20-year-old HIV-positive person was 19 years.

Since then, researchers have developed new drugs to treat HIV, and highly effective HIV treatment is currently available.

Nowadays, if people begin ART early and receive regular treatment, they can live long and healthy lives.

Acute retroviral syndrome is the initial, acute stage of an HIV infection.

Not everyone experiences this set of symptoms after contracting HIV.

However, those who do get symptoms can expect them to last from a few days to a few weeks.

For most people, the symptoms of ARS resemble those of the flu and are mild. Some people may have swollen lymph nodes for much longer, though.

Early HIV testing and diagnosis are essential because individuals who receive the correct medication regimen can expect a near-normal life expectancy.