Acute HIV Infection

What is acute HIV infection?

Acute HIV infection, also known as an early or primary retroviral infection, is a condition that develops within two to four weeks of contracting human immunodeficiency virus (HIV).

Symptoms of acute HIV infection are similar to other viral infections, such as the flu or mononucleosis (mono or glandular fever). For this reason, many people do not realize they have been infected with HIV. A blood test is the best way to confirm an HIV infection.

There are two types of HIV: HIV-1 and HIV-2. HIV-1 is the more common form of HIV found in the United States. The term HIV in this resource refers to HIV-1, unless otherwise stated.[1]

HIV attacks the body's immune cells. Without treatment, a person with HIV becomes more likely to develop infections or infection-related cancers. The last stage of HIV infection is AIDS (acquired immunodeficiency syndrome), when the immune system is severely damaged.[2]

There is currently no effective cure for HIV infection but, with the right treatment and medical care, the outlook for people with HIV is good.

Symptoms of acute HIV infection

Many people develop symptoms of acute HIV infection two to four weeks after contracting HIV. Symptoms can last for several weeks and are similar to other viral infections such as flu. Signs and symptoms can include the following, starting with the most common:[3][4][5][6]

  • Mouth ulcers
  • Red rash
  • Aching muscles
  • Joint pains
  • Unintentional weight loss
  • Fever
  • Loss of coordination
  • Tiredness
  • Headache
  • Swollen lymph nodes
  • Sore throat
  • Diarrhea

Some HIV-infected people do not have any symptoms, or may have symptoms that are mild and not particularly troublesome.

All these symptoms can also be caused by other illnesses. If a person has symptoms following potential exposure to HIV, they should be tested for HIV as soon as possible.[2]

Causes and stages of acute HIV infection

HIV is caused by a retrovirus which attacks the body’s immune system, specifically CD4 blood cells which are responsible for fighting infections. During acute HIV infection, the HIV retrovirus destroys a lot of CD4 cells as it replicates. This can cause some people to fall ill with flu-like symptoms.

Acute HIV infection is the first stage of HIV infection. It is followed by two further stages:[2]

Clinical latency, also known as asymptomatic HIV infection or chronic HIV infection. The HIV retrovirus continues to replicate within the body, but at low levels. The infected person may not experience any HIV-related symptoms, but can still transmit the virus to other people. Without treatment, this stage can last around 10 years. Towards the end of this phase, the person’s CD4 count starts to decrease and they may start to show symptoms.

AIDS (acquired immunodeficiency syndrome) is the final stage of HIV infection. Without treatment, a person can expect to develop AIDS after approximately 10 years. During this stage, a person’s immune system is badly damaged and they are susceptible to severe illnesses such as chronic cryptosporidiosis, lymphoma and pneumonia. Without treatment, a person with AIDS will typically only live around three years.[7]

Treatment can slow the progression of HIV infection, often by decades.

Who is at risk of acute HIV infection?

HIV can affect people of any age, sexual orientation or race, in any part of the world. However, certain groups of people are more at risk of contracting HIV than others. These can include people who:[8]

  • Have unprotected sex, particularly anal sex, with multiple partners
  • Share needles when injecting substances

HIV can be spread in the following ways:[8][9]

  • Contact with infected blood
  • Contact with infected semen
  • Contact with infected vaginal and/or rectal fluids
  • From mother to child during pregnancy or birth if the pregnant woman has HIV
  • Less commonly, during breastfeeding if the breastfeeding woman has HIV and is not on antiretroviral treatment[10]
  • Sharing needles, syringes or drug preparation equipment with someone who has HIV

Other physical contact, such as hand-holding, kissing or hugging, does not transfer HIV..

Risks of transmission during acute HIV infection

During the acute HIV infection phase, there are very high levels of HIV in the body. This means the risk of transmitting HIV to another person is high.[11]

Diagnosis of acute HIV infection

The only way to confirm an acute HIV infection diagnosis is to be tested for HIV. There are different types of tests, depending on how long it has been since the person’s potential exposure to the HIV virus. Testing will involve either a sample of fluid swabbed from the mouth, or a blood sample.

Antibody tests are the most common tests for HIV, including rapid tests and home tests. Antibody tests screen for HIV-1 antibodies, which are produced by the immune system after exposure to the HIV virus. It takes at least three weeks, and sometimes up to 12 weeks, for a person to develop enough antibodies to be detectable in this type of test.[12]

Combination, or fourth-generation, tests detect both HIV-1 antibodies and p24 antigens. The p24 antigen is part of the HIV virus and can be detected as early as two weeks after infection in some people, although for others it can take up to six weeks. The amount of p24 antigen in the blood is gradually reduced by antibodies, which makes it unsuitable for use in diagnosing HIV after the very early stages.[12][13]

Nucleic acid tests detect the HIV virus itself in the blood. The test is expensive and usually only used in cases where high-risk exposure has occurred, or the person has symptoms of acute HIV infection. Nucleic acid tests can detect the HIV virus as early as one week after infection in some people, but it may take up to four weeks until detection is possible for others.[12]

HIV test window period

The window period is the amount of time between when a person is first infected and when a test is able to accurately diagnose HIV infection:[14] The following numbers are a guide, as the exact numbers may vary between tests and labs.

  • Antibody tests: 21 to 84 days after infection
  • Fourth generation tests: 13 to 42 days after infection
  • Nucleic acid tests: seven to 28 days after infection

The first number for each test is the earliest possible time that an HIV infection can be detected with that test. However, each person responds differently to infection, so, in some cases, HIV may not be detectable until much later (indicated by the second number). If an early HIV test produces a negative result, it is advisable to have another test after the end of the window period.

Treatment of acute HIV infection

Acute HIV infection is treated with antiretroviral drugs (ARVs), which are drugs specially designed to treat retroviruses. People with HIV are prescribed a combination of antiretroviral drugs, which together are known as antiretroviral therapy (ART).

Antiretroviral therapy reduces the amount of virus (viral load) in the body. It does not cure HIV infection, but, taken correctly, it can slow progression of the condition from one stage to the next. For example, one recent study showed that a person diagnosed at age 20 who has appropriate treatment now has a life expectancy very close to that of a person without HIV.[15]

Antiretroviral therapy should be started as soon as possible after diagnosis. It is very important to take antiretroviral medication correctly. Missing doses or stopping and restarting treatment can lead to drug resistance, which can reduce future treatment options.[16]

Side-effects of ART may lead some people to consider stopping their medication. However, the long-term benefits of ART exceed the difficulties posed by some side-effects. It is very important not to stop taking ART without speaking with a doctor, who may be able to prescribe a more comfortable combination of antiretroviral drugs. More recent developments in ART mean that intolerable side-effects are fewer than in the past.[17]

Side-effects associated with taking antiretroviral drugs include:[16][18]

  • Nausea
  • Vomiting
  • Tiredness
  • Headache
  • Insomnia
  • Dry mouth
  • Diarrhea
  • Fever
  • Dizziness
  • Rash
  • Muscle pain

Doctors can generally tailor ART for a particular person to counter potential adverse effects, and a person may take various different antiretroviral drugs over the course of a lifetime.[17]

More serious side-effects can emerge after taking antiretroviral drugs for a long time. These include:[18][17]

People who have contracted HIV become more susceptible to other medical conditions, so they will benefit from lifestyle changes such as eating a healthy and balanced diet, practicing safe sex and reducing stress levels. HIV infection often has a large emotional and psychological impact, so counseling and social support should be available throughout treatment.

Post-exposure Prophylaxis (PEP)

PEP is a combination of antiretroviral drugs intended for use in emergency situations. When taken correctly, PEP can help to prevent HIV infection, but it is not 100 percent effective. Post-exposure Prophylaxis (PEP) must be started as soon as possible after, and within 72 hours of, potential exposure to HIV infection.[19]

PEP must be taken exactly as directed for 28 days. The drugs may cause side-effects, such as:[19][20][21]

  • Nausea
  • Vomiting
  • Headaches
  • Tiredness
  • Diarrhea

Prevention of acute HIV infection

There are ways to minimize the risk of contracting HIV, or passing the infection on to other people:[22]

  • Practice safe sex: use condoms during all types of sexual contact and limit the number of partners
  • Practice safe needle use: use only sterile needles and equipment if injecting substances. Safe needle use should also be observed by healthcare workers and tattooists
  • Get diagnosed early, which can inform choices such as treatment and behavior toward other people

Anyone who is sexually active is recommended to get tested for HIV and other sexually transmitted diseases at least once a year. Any positive results should be disclosed to sexual partners so precautions can be taken. More frequent testing is recommended for anyone in a high risk group, such as someone who:[23]

  • Is in a relationship with a person who is HIV-positive
  • Has multiple sexual partners
  • Shares needles or drug equipment

Pre-exposure prophylaxis (PrEP)

Pre-exposure prophylaxis (PrEP) is another way of reducing the risk of acute HIV infection. PrEP is a combination of two medications that, taken daily, can lower a person’s chances of becoming infected with HIV.

PrEP is typically recommended for people who are considered to be at high risk of contracting HIV. This can include anyone who:[23]

  • Is in a relationship with a person who is HIV-positive
  • Is considering getting pregnant with a person who is HIV-positive
  • Has unprotected sex with people who are also at high risk of contracting HIV, such as people who inject drugs
  • Shares needles or drug equipment

Taken as directed, PrEP can reduce the risk of becoming infected with HIV by:[23]

  • More than 90 percent during sex
  • More than 70 percent when injecting drugs

PrEP should still be used alongside condoms as it does not provide protection against other STDs, such as gonorrhea.

Other names for acute HIV infection

  • Human immunodeficiency virus infection

  1. AIDSinfo. “HIV-1” Accessed June 21, 2018.

  2. Centers for Disease Control and Prevention. “About HIV/AIDS.” January 2018. Accessed June 21, 2018.

  3. HIV.gov. “What Are HIV And AIDS?” May 2017. Accessed June 21, 2018.

  4. AIDSinfo. “Considerations for Antiretroviral Use in Special Patient Populations.” October 2017. Accessed June 21, 2018.

  5. Avert. “Symptoms and stages of HIV infection.” February 2017. Accessed June 21, 2018.

  6. American Family Physician. “Diagnosis and Initial Management of Acute HIV Infection.” May 2010. Accessed June 24, 2018.

  7. Centers for Disease Control and Prevention. “Opportunistic Infections.” May 2017. Accessed June 21, 2018.

  8. Centers for Disease Control and Prevention. “HIV Transmission.” January 2018. Accessed June 21, 2018.

  9. AIDSinfo. “The Basics of HIV Prevention.” May 2018. Accessed June 21, 2018.

  10. World Health Organization. “Breast is always best, even for HIV-positive mothers.” January 2010. Accessed June 24, 2018.

  11. AIDSinfo. “The Stages of HIV Infection.” August 2017. Accessed June 21, 2018.

  12. HIV.gov. “HIV Testing Overview.” May 2018. Accessed June 21, 2018.

  13. aidsmap. “p24 antigen.” June 2012. Accessed June 21, 2018.

  14. Centers for Disease Control and Prevention. “The Window Period.” Accessed June 21, 2018.

  15. The Lancet. “Survival of HIV-positive patients starting antiretroviral therapy between 1996 and 2013: a collaborative analysis of cohort studies.” May 2017. Accessed July 17, 2018.

  16. HIV.gov. “HIV Treatment Overview.” May 2017. Accessed June 21, 2018.

  17. AIDSinfo. “Limitations to Treatment Safety and Efficacy.” October 2017. Accessed June 21, 2018.

  18. AIDSinfo. “HIV Medicines and Side Effects.” October 2017. Accessed June 21, 2018.

  19. Centers for Disease Control and Prevention. “PEP.” May 2018. Accessed June 21, 2018.

  20. Ending HIV. “5 Tips for Using PEP Effectively.” November 2015. Accessed June 21, 2018.

  21. Terrence Higgins Trust. “PEP.” April 2016. Accessed June 21, 2018.

  22. Centers for Disease Control and Prevention. “HIV Prevention.” March 2018. Accessed June 21, 2018.

  23. Centers for Disease Control and Prevention. “PrEP.” March 2018. Accessed June 21, 2018.