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HIV (human immunodeficiency virus) causes disease by gradually destroying the immune system, making it harder for the body to defend itself from otherwise harmless infections. When the immune defenses are compromised, a person can develop AIDS (acquired immunodeficiency syndrome).

HIV is mainly transmitted through anal or vaginal sex. But it can also be transmitted when people who inject drugs share needles, from a pregnant person to a fetus during pregnancy or childbirth, or from a breastfeeding parent to a nursing infant.

An illustration with information about HIV/AIDS (What Are the Differences?)

Illustration by Mira Norian for Verywell Health

Although incurable, chronic HIV infection can be controlled with antiretroviral drugs, allowing people to live long, healthy lives while preventing the transmission of the virus to others.

This article explains the causes and symptoms of HIV/AIDS, including how the disease is diagnosed and treated. It also offers tips on how to live well with HIV as well as what to expect if you are newly diagnosed.

HIV and AIDS: What Are the Differences?

HIV is a virus that can lead to AIDS if the infection is left untreated.

HIV causes disease by targeting and killing a type of white blood cell called CD4 T-cells, which activate the immune system whenever there is a foreign invader. When enough of these cells are depleted, the body becomes "blind" to diseases it could otherwise fight off.

AIDS is the final stage of HIV. It occurs when the immune system is fully compromised, leaving the body exposed to an ever-widening range of life-threatening opportunistic infections, diseases that can occur in people with weakened immune systems.

Having HIV means you can get AIDS, but it doesn't mean you will get AIDS. Today, AIDS is largely the result of untreated HIV infection.

HIV-Positive and HIV-Negative Meanings

HIV-positive means that you have HIV based on two tests that confirm the presence of the virus in your blood. The tests are extremely accurate, and false-positive results, which indicate the condition is present when it actually is not, are rare. Once you have been diagnosed with HIV, you will always have HIV.

HIV-negative means that there is no evidence of the virus in your blood. However, it doesn't necessarily mean that you are clear of the infection.

If you test too early after an exposure—during the window period, when the body has not yet triggered an ample immune response—your test may return a false-negative result, meaning that you have the virus while the test result reads otherwise.

AIDS Meaning 

AIDS is the stage of infection in which you are said to be immunocompromised and at risk of potentially serious opportunistic infections. AIDS is said to occur when either:

  • You have fewer than 200 CD4 T-cells per microliter (cells/µL) of blood (referred to as your CD4 count). A normal CD4 count is between 500 and 1,000 cells/µL.
  • Or, you have one of over two dozen diseases classified as AIDS-defining conditions by the Centers for Disease Control and Prevention (CDC). These are diseases rarely seen outside of people with advanced HIV and can occur at CD4 counts above 200.

Stages of HIV

HIV progresses in the following three stages:

  1. Acute stage: This is the period immediately following exposure, at which time the immune system activates to fight the invaders. While the infection will eventually be controlled, the virus doesn't disappear. Instead, it hides in tissues where it continues to silently replicate.
  2. Chronic stage: This is a prolonged period of years and even decades during which the virus gradually depletes CD4 T-cells, often with few notable symptoms.
  3. AIDS: This is the most advanced stage of HIV. If left untreated, HIV is inevitably fatal, with a median survival time of eight to 10 years.

Causes: How Do You Get HIV/AIDS?

HIV is found in high concentrations in blood, semen, vaginal fluids, anal secretions, and breast milk. Because of this, HIV is most commonly spread by:

HIV does not survive in saliva, urine, or sweat due to enzymes and acids in those fluids that are hostile to the virus.

Unlikely modes of transmission include oral sex, tattooing or body piercing, dental work, and blood transfusions. You cannot get HIV from food, utensils, toilet seats, kissing, touching, mosquito bites, or personal care items.

Risk factors for HIV include:

Where Did HIV Come From?

Genetic research suggests that HIV is a mutation of the simian immunodeficiency virus (SIV) found in chimpanzees of Central Africa. The virus is likely to have jumped from chimpanzees to humans due to blood exposure or the consumption of bushmeat (raw or not fully cooked meat from wild animals).

HIV Symptoms

Not everyone gets symptoms during the acute and chronic stages of HIV. Those who do often have generalized, nonspecific symptoms that are easily mistaken for other illnesses.

Acute Symptoms

During an acute infection, upwards of 50% of people will experience short-term, flu-like symptoms (referred to as acute retroviral syndrome or acute seroconversion).

Symptoms of acute HIV infection include:

  • Mild fever
  • Fatigue
  • Headache
  • Sore throat
  • Muscle aches
  • Joint pain
  • Swollen lymph nodes
  • A characteristic rash

Chronic Symptoms

During the chronic stage of infection, it is not uncommon to have persistently swollen lymph nodes (lymphadenopathy), although most cases tend to ease over time. As the infection silently progresses, people often experience chronic fatigue or develop immune-associated medical conditions like:

Symptoms of HIV in Females and Males

HIV symptoms are largely the same whether you are female or male. With that said, females with HIV may experience frequent yeast infections, irregular periods, abnormal bleeding or spotting, and chronic pelvic pain. Males with HIV may experience pain with ejaculation, erectile dysfunction, a reduced sex drive, and abnormal breast growth (gynecomastia).

AIDS Symptoms

The symptoms of AIDS vary by the type of infection you get. These are examples from four of the more common AIDS-defining conditions:

  • Tuberculosis: This bacterial lung infection can cause fever, night sweats, chest pain, weight loss, weakness, and the coughing up of blood.
  • Pneumocystis pneumonia: This fungal lung infection causes fever, trouble breathing, chest pain, and a dry cough with little or no mucus.
  • Esophageal candidiasis: This fungal infection of the esophagus (feeding tube) causes fever, nausea, chest soreness, pain when swallowing, and difficulty swallowing.
  • HIV wasting syndrome: This poorly understood condition causes unexplained weight loss of more than 10% of a person's body weight.

Testing to Know If You Have HIV/AIDS

HIV is mainly diagnosed with blood tests, but there are also saliva-based tests that can provide a rapid, initial diagnosis.

The most common method of HIV testing in the United States is a combination antibody/antigen test. This test involves two different technologies—called an enzyme-linked immunoassay (ELISA) and polymerase chain reaction (PCR)—that detect two specific proteins in a sample of blood:

  • HIV antibodies: These are proteins produced by the immune system in response to HIV.
  • HIV antigens: These are proteins on the surface of HIV that serve as its unique identifier.

There are also rapid tests used in clinics and hospitals—called OraQuick ADVANCE—that can detect HIV antibodies from a swab of saliva. Results are returned in around 20 minutes. If the results are positive, a blood test is needed to confirm the results.


Because people sometimes avoid HIV testing out of the fear of stigma or disclosure, the Food and Drug Administration (FDA) approved an at-home version of OraQuick ADVANCE, called the OraQuick In-Home HIV Test, in 2012.

The wand-shaped device works on the same principle as the OraQuick ADVANCE and can also return results in around 20 minutes. While the current generation of the OraQuick In-Home HIV Test is extremely accurate, it is vulnerable to user error and occasional false-negative results.

If a positive result is received, a blood test at a clinic or lab is still needed to confirm the diagnosis.

How Is HIV Spread?

As a disease that is mainly spread through sex or sharing needles, HIV is known to affect some groups more than others. The infection rate in these at-risk groups is fueled not only by sexual practices but also by biological, social, and economic vulnerabilities that predispose them to HIV.

In the United States, these include:

  • Men who have sex with men (MSM): Gay, bisexual, and other men who have sex with men have a 1 in 6 lifetime risk of HIV and account for 71% of new HIV infections.
  • Black women: Among all women, Black women account for the largest share of new HIV diagnoses (58%).
  • Transgender women: The risk of HIV in transgender women is no less than 34 times greater than that of the general population.
  • Youth aged 13 to 24 years: According to the CDC, teens and young adults account for 26% of all new HIV diagnoses.
  • Injecting drug users: People who inject drugs account for 1 in 10 new infections in the United States and are 22 times more likely to get HIV than nondrug users.

Intersecting risk factors—including systemic racism, poverty, and unequal access to health care—further amplify the risk in certain groups.

HIV/AIDS Treatment

HIV is treated with antiretroviral drugs. Antiretroviral drugs work by blocking a stage in the virus's life cycle. Without the means to make copies of itself, HIV is suppressed to undetectable levels, where it can do the body little harm.

Antiretroviral drugs do not cure HIV. If you stop treatment, the virus will return.

Antiretroviral therapy involves the combination of two or more drugs of different classes. There are six classes of antiretroviral drugs, each classified by the stage of the cycle they inhibit. They include:

In the United States, the usual first-line treatment is with two NRTIs. Though antiretrovirals are typically taken once daily by mouth, a once-monthly injectable drug called Cabenuva (cabotegravir/rilpivirine) was approved by the FDA in 2021 as an alternative to oral drugs.

As of March 2023, there were 48 different HIV drugs approved by the FDA, including 22 fixed-dose combination drugs that contain two or more antiretroviral agents.

Complications of HIV/AIDS

Advanced HIV infection can affect nearly every organ system of the body. While the majority of complications are the result of an opportunistic infection that occurs in people with weakened immune systems rather than the virus itself, there are a few in which HIV plays a direct role (like HIV wasting and AIDS dementia).

Many AIDS-defining conditions are characterized by disseminated disease in which an infection spreads beyond its usual location (such as the skin or lungs) to distant parts of the body. With some, the infection may become systemic, meaning that the entire body is involved.

Organ System AIDS-Defining Condition
Multiple organs Bacterial infections, multiple or recurrent

Cervical cancer (invasive)




Herpes simplex virus beyond the skin


Mycobacterium avium complex

Mycobacterium outside of the lungs

Salmonella septicemia
Brain HIV encephalopathy (AIDS dementia)

Primary lymphoma of the brain

Progressive multifocal leukoencephalopathy

Toxoplasmosis of the brain
Eyes Cytomegalovirus retinitis
Gastrointestinal Cryptosporidiosis



Salmonella infection
Lymphatic system Burkitt lymphoma

Immunoblastic lymphoma
Respiratory Candidiasis of the lungs

Lymphoid interstitial pneumonia

Mycobacterium tuberculosis

Pneumocystis jirovecii pneumonia

Recurrent pneumonia
Skin Kaposi's sarcoma

HIV/AIDS: Support and Resources 

For some, HIV can be life-changing and difficult to comprehend. Finding the right support can help you come to terms with your diagnosis and overcome many of the challenges of living with HIV, including disclosure, intimacy, sexuality, and health care.

If you are diagnosed with HIV, you may be better able to cope if you do the following:

  • Build a support network: This not only includes trusted friends and loved ones who will safeguard your confidentiality but also online and in-person support groups.
  • Practice disclosure: Start by educating yourself about HIV, including how it is spread and prevented. By having a firm grasp of the facts, you'll be more confident when disclosing your status to others.
  • Maintain consistent care: Studies have shown that people who remain in treatment are better able to maintain adherence and have better long-term outcomes than those who don't.
  • Find financial assistance: You can reduce financial stress by accessing a drug manufacturer's patient-assistance program, the government's AIDS Drug Assistance Program (ADAP), and nonprofit co-pay assistance programs like the PAN Network and Patient Advocate Foundation (PAF).
  • Address your emotional well-being: If you are unable to cope, do not hesitate to ask your healthcare provider for a referral to a therapist or psychiatrist who can offer counseling and prescribe medications if needed.

HIV, Sex, and Intimacy

HIV doesn't mean the end of your sex life. In fact, it allows you to open a discussion about sex and ways to enjoy it while fully protecting each other.

This may include:


Due to advances in testing and treatment, the outlook for a person newly diagnosed with HIV is good. With the appropriate uninterrupted treatment, you can expect to live a normal to near-normal life expectancy.

In fact, a 2020 study from Harvard Medical School suggests that the average life expectancy of individuals newly diagnosed with HIV at age 21 is 77 years. That's just five years short of the average life expectancy of someone without HIV.

At the same time, starting treatment early, when your immune system is intact, cuts the risk of HIV-related and non-HIV-related illnesses (including heart disease and certain cancers) by more than half compared to people who delay treatment.

Despite the benefits of treatment, 1 in 8 people living with HIV in the United States remain undiagnosed. Of those who are diagnosed, only 70% are able to sustain an undetectable viral load.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By James Myhre & Dennis Sifris, MD
Dennis Sifris, MD, is an HIV specialist and Medical Director of LifeSense Disease Management. James Myhre is an American journalist and HIV educator.