HIV is a sexually transmitted infection (STI). Without treatment, HIV weakens a person’s immune system and can lead to acquired immune deficiency syndrome (AIDS).

People may acquire HIV through bodily fluids such as blood, semen, breast milk, and vaginal and anal fluids.

There is no permanent cure for HIV. However, a person can manage the condition with treatment. This can slow the disease’s progression and prolong a person’s life.

About 1.2 million people in the United States are living with HIV.

This article explains how people transmit HIV and how to help prevent and treat it.

HIV is an STI that spreads from one person to another through blood, breast milk, semen, or vaginal secretions.

A few ways that a person can contract HIV include:

  • engaging in anal, oral, or vaginal sex with a person who has HIV
  • sharing needles or other injection equipment with a person who has HIV
  • perinatal transmission — when a parent transmits HIV to an infant during pregnancy, childbirth, or nursing

It is not possible to contract HIV by:

  • hugging, holding hands, or kissing
  • being near someone with HIV
  • consuming food that someone with HIV has handled
  • sitting on toilet seats that a person with HIV has used
  • donating blood

A person with HIV can avoid transmitting it to sexual partners or infants by taking medication for HIV.

A type of HIV medication called antiretroviral therapy (ART) reduces a person’s viral load — the amount of HIV present in the blood.

If the viral load is low enough that tests cannot detect it, a person with HIV will not transmit the virus to others through sex, sharing injection equipment, pregnancy, childbirth, or nursing.

A person with an undetectable viral load can also live a long and healthy life. The earlier a person starts ART, the better.

Most newly diagnosed people who diligently follow their ART regimen will get the virus under control within 6 months.

HIV is a progressive infection that can develop into a more serious condition called acquired immunodeficiency syndrome (AIDS). However, having HIV does not guarantee that a person will develop AIDS.

HIV has three stages:

  • Stage 1 (acute): People may experience flu-like symptoms. They have a high level of HIV in their blood and may easily spread it to others.
  • Stage 2 (chronic): HIV is still active and reproducing within the person’s body. They can still spread it to others, but they may not experience symptoms. This stage can last 10 years or longer.
  • Stage 3 (AIDS): This is the most severe stage. People with AIDS have a damaged immune system and can transmit HIV to others. They are more vulnerable to opportunistic infections and serious illnesses, such as certain cancers. Without treatment, the life expectancy for a person with AIDS is typically 3 years, but this could shorten if an opportunistic illness develops.

If a person does not receive treatment, HIV may progress through the stages. However, receiving ART will slow the progression of HIV. With treatment, people with HIV can live long and healthy lives.

Due to the treatments available, it is less common today for a person with HIV to develop AIDS than it was years ago.

Some people with HIV may be asymptomatic. Others experience flu-like symptoms, especially within a few weeks of first contracting the virus.

The only way to be certain that a person has HIV is to get tested. This is why it is important to get tested even if there are no specific symptoms.

Some possible symptoms of HIV include:

Generally, HIV tests are very accurate, but no test can effectively detect the virus immediately after infection. How soon someone can get a proper diagnosis depends on the type of test.

There are three HIV tests:

  • antibody tests
  • antigen or antibody tests
  • nucleic acid tests (NAT)

The Centers for Disease Control and Prevention (CDC) recommend that everyone between the ages of 13 and 64 years receive an HIV test at least once.

People should get tested regularly if they have certain risk factors. People who should get tested at least once a year include:

  • men who have or have had sex with men
  • people who have had anal or vaginal sex with someone with HIV
  • those with more than one sexual partner
  • people who share or have shared needles and other injection equipment with others
  • people who have exchanged sex for drugs or money
  • those who have received a diagnosis of or treatment for another STI
  • those who have received a diagnosis of or treatment for tuberculosis (TB) or hepatitis
  • people who have had sex with anyone else at risk of HIV or with an anonymous partner

Learn more about HIV testing here.

Although all risk factors are the same, HIV affects certain groups more than others.

The CDC notes that 70% of new HIV cases in the United States in 2019 were among gay and bisexual men.

Black/African American people also experience disproportionate cases of HIV, accounting for 42% of new HIV diagnoses in the U.S. in 2019.

HIV affects Black/African American gay and bisexual men more than any other groups in the U.S.

Trans women who have sex with men may also be at a higher risk of contracting HIV. In a 2019 survey of adult trans women across seven U.S. cities, up to 42% reported having HIV. And 62% of Black trans women reported having HIV in this study.

This disproportion in HIV cases may be due to structural and social issues, such as:

  • HIV stigma
  • institutional and social homophobia, racism, and transphobia
  • poverty due to discrimination
  • barriers to healthcare due to discrimination
Learn more

Learn more about HIV, discrimination, and more.

According to the CDC, residents of the United States who get syphilis, gonorrhea, or herpes often have HIV or are at risk of getting it in the future.

Researchers associate HIV with gonorrhea more than chlamydia, which is common in young women. A group of studies found that people with HSV-2, a herpes virus, were three times more likely to contract HIV.

An older 2014 study also found that having syphilis may increase the likelihood of contracting or transmitting HIV.

Clinicians can test for HIV with a blood test.

People who come in contact with the virus should get tested quickly. However, it can take a while for the body to develop antibodies against the virus. Follow-up tests may help if the initial test is too early.

Most clinics offer HIV testing along with counseling. During the test, the healthcare professional will ask for symptoms, previous medical records, and any risk factors before performing a physical examination.

A person can use ART to slow the progression of HIV and help avoid developing AIDS. Treating HIV early will help a person live a long and healthy life.

Using ART will also help prevent a person from passing HIV to others, if it reduces their viral load to an undetectable level.

Learn more

Learn more about HIV, ART, and HIV treatment.

A person who receives ART can live a long and healthy life with HIV.

Other things that influence life expectancy include:

  • receiving an HIV test early
  • starting ART immediately after diagnosis
  • following an ART regimen diligently
  • receiving therapy and counseling

If a person does not receive treatment for HIV, the disease can progress through its stages. It can take up to 10 years for HIV to progress into AIDS.

Once a person develops AIDS, their life expectancy is typically up to 3 years.

Reducing exposure to risk factors can help a person avoid contracting HIV.

A person without HIV can take the following steps to prevent it:

  • Avoid sharing needles or other sharp objects: A person can contract HIV from sharing needles that have touched the blood of a person with HIV.
  • Try PEP: Using postexposure prophylaxis (PEP) can reduce the risk of getting HIV after a potential exposure. It consists of three medications that last for 28 days. This treatment should begin as soon as possible but not more than 72 hours after exposure.
  • Consider PrEP: Pre-exposure prophylaxis (PrEP) combines two pills. It can lower the risk of contracting HIV, especially when the person takes it properly.
  • Use condoms during sex: Learn the correct way to use a condom and use it every time during sex. Note that HIV can spread via pre-seminal fluids in men.
  • Frequently undergo testing: A person should frequently receive tests for HIV and other STIs.

Because HIV disproportionately affects certain groups, and due to the stigma around HIV, people may lack the social, financial, and familial support they need.

According to the CDC, a person with HIV or AIDS may also qualify for disability benefits or reduced healthcare costs. A person should discuss this with a healthcare professional.

A healthcare professional may also be able to refer a person with HIV to other charities, support groups, and therapy sessions that may help them with their treatment journey.

This section answers some frequently asked questions about HIV.

Which STD can cause HIV?

People who have STIs such as syphilis, gonorrhea, and herpes may be more at risk of getting HIV.

However, no STI can cause HIV. HIV is an STI itself, and a person can contract it by engaging in sexual activities with a person who already has it.

Is HIV a bacterial or viral STD?

HIV is a viral STI. Some examples of other common STIs include human papillomavirus (HPV), herpes, chlamydia, and syphilis.

HIV is a viral STI that weakens the body’s immune system.

If a person with HIV receives treatment, they can live a long and healthy life. Early testing can help people start treatment as quickly as possible and improve their outlook.