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HIV is a virus that targets and alters the immune system, increasing the risk and impact of other infections and diseases. Without treatment, the infection might progress to an advanced stage called AIDS.

Due to medical advances, people with HIV and access to quality healthcare very rarely develop AIDS once they have started taking HIV treatment.

As experts such as the World Health Organization (WHO)Trusted Source observe, HIV has become a manageable condition, and many people with HIV have long, healthy lives.

The life expectancy of a person with HIV is now approaching that of someone who tests negative for the virus, provided that the person takes medications called antiretroviral therapy on an ongoing basis.

As of 2019, around 68% of adultsTrusted Source and 53% of children with HIV worldwide were receiving lifelong treatment.

In this article, we explore HIV and AIDS, including their symptoms, causes, and treatments.

What is HIV?


HIV stands for “human immunodeficiency virus,” and it attacks immune cells called CD4 cells. These are types of T cell — white blood cells that circulate, detecting infections throughout the body and faults and anomalies in other cells.

HIV targets and infiltrates CD4 cells, using them to create more copies of the virus. In doing so, it destroys the cells and reduces the body’s ability to combat other infections and diseases. This increases the risk and impact of opportunistic infections and some types of cancer.

It is worth noting, however, that some people have HIV for long periods without experiencing any symptoms.

HIV is a lifelong condition, but treatments and certain strategies can prevent the virus from transmitting and the infection from progressing.

What is AIDS?

AIDS stands for “acquired immunodeficiency syndrome.” It is an advanced stage of HIV infection.

Doctors identify AIDS as having a CD4 count of fewer than 200 cells per cubic millimeter. Also, they may diagnose AIDS if a person has characteristic opportunistic infections, associated types of cancer, or both.

When a person with HIV does not receive treatment, AIDS likely develops, as the immune system gradually wears down. However, advances in antiretroviral treatments have made this progression to AIDS increasingly less common.

In 2018, there were more than 1.1 million people living with HIV in the United States and 6,000 deaths related to AIDS.

For more in-depth information and resources on HIV and AIDS, visit our dedicated hub.


HIV can transmit when body fluids containing the virus come into contact with a permeable barrier in the body or small breaks in moist tissues of areas such as the genitals.

Specifically, HIV can transmit via:



pre-seminal fluid

vaginal fluids

rectal fluids

breast milk

The virus cannot transmit through saliva, so a person cannot contract HIV through open-mouthed kissing, for example.

One of the main causes of HIV transmission in the U.S. is anal or vaginal intercourse. For the transmission to happen, the people must not be using barrier protection, such as a condom, or taking pre-exposure prophylaxis (PrEP), a treatment that aims to prevent HIV transmission among people with known risk factors.

Another main cause of HIV transmission in the country is sharing equipment for injecting drugs.

Less commonly, HIV transmits to babies during pregnancy, childbirth, or breastfeeding.

Also, there is a chance of transmission in blood transfusions, though the risk is extremely low when blood donations are effectively screened.

Undetectable = untransmittable

HIV can only transmit through fluids that contain a certain amount of the virus. If a person has undetectable levels of HIV, the virus cannot transmit to another person.

Some people use a shorthand to refer to the fact that undetectable levels of HIV are untransmittable: U=U.

Doctors consider HIV to be undetectable when the amount of the virus in the body is so low that a blood test cannot identify it.

Having undetectable levels requires a person to continually receive effective treatment and follow the recommended plan carefully, which usually involves taking medications every day.

A person with undetectable levels still has HIV, and regular monitoring with blood tests is key to maintaining this status.

Progression to AIDS

The chances of HIV progressing to AIDS vary widely from person to person and depend on many factors, including the:

person’s age

body’s ability to defend against HIV

accessibility of quality healthcare

presence of other infections

person’s genetic resistance to certain strains of HIV

strain of HIV, as some are drug resistant


For the most part, other infections — with bacteria, other viruses, fungi, or parasites — cause the more pronounced symptoms of HIV.

Early symptoms of HIV

Some people with HIV have no symptoms for months or even years after contracting the virus. Partly because of this, 1 in 7 people with HIV in the U.S. do not know that they have it.

While a person with no symptoms may be unlikely to seek care, there is still a high risk of transmission. For this reason, experts recommend regular testing, so that everyone is aware of their HIV status.

Meanwhile, around 80% of people with HIV develop flu-like symptoms around 2–6 weeks after contracting the infection. These symptoms are collectively called acute retroviral syndrome.

Early symptoms of HIV may include:

a fever


sweating, particularly at night

enlarged glands or swollen lymph nodes

a diffuse rash



pain, including joint pain

muscle aches

a sore throat

thrush, or a yeast infection

unintentional weight loss, with advancing HIV

Read about the timeline of HIV infection here.

These symptoms result from the immune system fighting off different types of infection. Anyone who has several of these symptoms and may have contracted HIV in the past 2–6 weeks should take a test.

Some symptoms of HIV vary by sex. Read more about symptoms in males and symptoms in females.

Asymptomatic HIV

After the symptoms of acute retroviral syndrome resolve, many people go on to experience no HIV symptoms for years.

While they feel well and appear healthy, the virus continues to develop and damage the immune system and organs. If the person does not take medication that prevents the replication of the virus, this slow process can continue for around 8–10 yearsTrusted Source.

However, taking antiretrovirals can stop this process and suppress the virus completely.

Late-stage HIV infection

If a person with HIV does not receive effective treatment, the virus weakens the body’s ability to fight infection, exposing it to serious illnesses.

When CD4 cells are severely depleted, at fewer than 200 cells per cubic millimeter, a doctor can diagnose AIDS, which is sometimes called stage 3 HIV.

The presence of certain opportunistic infections, involving bacteria, viruses, fungi, or mycobacteria, also help a doctor identify AIDS.

Symptoms of AIDS can include:

blurred vision

a dry cough

night sweats

white spots on the tongue or mouth

shortness of breath, or dyspnea

swollen glands lasting for weeks

diarrhea, which is usually persistent or chronic

a fever of over 100°F (37°C) that lasts for weeks

continuous fatigue

unintentional weight loss

A person with AIDS has a significantly increased risk of developing a life threatening illness. Without treatment, people with AIDS typically live for around 3 yearsTrusted Source after the diagnosis.

However, by taking other medications alongside HIV treatment, a person with AIDS can control, prevent, and treat serious complications.

When a person with HIV takes effective treatment, the infection may never progress to stage 3. Treatment can also help a person recover some lost immune function, which will help ward off severe infections.

Opportunistic infections and cancer

Late-stage HIV reduces the ability of the body to combat a range of infections and associated complications and types of cancer.

Current treatment is often effective enough to keep many infections at bay. If a person with HIV does not receive treatment, latent infections that once caused minimal or no health problems can pose a serious risk. Doctors refer to these infections as opportunistic.

Below are some opportunistic infectionsTrusted Source that can signal to a doctor that a person has AIDS:

candidiasis of the bronchi, trachea, esophagus, and lungs




cytomegalovirus disease (CMV)




infections with mycobacteria

recurrent pneumonia

Pneumocystis jirovecii pneumonia

chronic intestinal isosporiasis

recurrent Salmonella septicemia


Candidiasis is a fungal infection that typically occurs in the skin and nails, but it often causes serious problems in the esophagus and lower respiratory tract in people with AIDS.

Inhalation of the fungus Coccidioides immitis causes coccidioidomycosis. A doctor may refer to this infection in healthy people as valley fever.

Cryptococcosis is an infection with Cryptococcus neoformans fungus. Any part of the body may be involved, but the fungus usually enters the lungs and triggers pneumonia. It may also lead to swelling of the brain.

Cryptosporidiosis is an infection with the protozoan parasite Cryptosporidium. It can lead to severe abdominal cramps and chronic, watery diarrhea.

CMV can cause a range of diseases, including pneumonia, gastroenteritis, and encephalitis, a brain infection. CMV retinitis a particular concern for people with AIDS. This is an infection of the retina, at the back of the eye, and it permanently impairs a person’s sight. It is a medical emergency.

Herpes results from infection with the herpes simplex virus (HSV). This virus usually transmits through sex or childbirth.

In a person with reduced immune function, herpes can cause painful cold sores around the mouth and ulcers on the genitals and anus that do not go away. These sores, rather than a herpes diagnosis, can indicate AIDS. Herpes can also infect the lungs or esophagus of someone with AIDS.

Histoplasmosis is an infection with the fungus Histoplasma capsulatum, and it causes extremely severe, pneumonia-like symptoms in people with advanced HIV. Histoplasmosis can also become progressive and widespread, affecting organs outside the respiratory system.

The bacteria Mycobacterium tuberculosis cause tuberculosis, and they can transfer through the air if a person with an active infection sneezes, coughs, or speaks. The signs and symptoms can include a severe lung infection, weight loss, a fever, and fatigue. Tuberculosis can spread to the brain and other organs.

Types of mycobacteria, including Mycobacterium avium and Mycobacterium kansasii are naturally present and tend to cause few problems. However, in a person with HIV, especially if it is in the later stages, these infections can spread throughout the body and cause life threatening health issues.

Many different pathogens can cause pneumonia, but a type of bacteria called Streptococcus pneumoniae can be one of the most dangerous for people with HIV. A vaccine for this bacterium is available, and everyone with HIV should receive it.

Meanwhile, infection with a fungus called Pneumocystis jirovecii can cause breathlessness, a dry cough, and a high fever in people with suppressed immune systems, including some people with HIV.

Chronic intestinal isosporiasis occurs when the parasite Isospora belli enters the body through contaminated food and water, causing diarrhea, fever, vomiting, weight loss, headaches, and abdominal pain.

When Salmonella bacteria enter the body — also usually via contaminated food or water — they can circulate and overpower the immune system, causing nausea, diarrhea, and vomiting. In this case, a doctor may diagnose recurrent Salmonella septicemia.

Toxoplasma gondii is a parasite that inhabits warm-blooded animals, including cats and rodents, and it is present in their feces.

Humans contract the resulting infection, called toxoplasmosis, by inhaling contaminated dust or eating contaminated food, including commercial meats. Toxoplasmosis can cause severe symptoms involving the lungs, retina, heart, liver, pancreas, brain, testes, and colon.

To reduce the risk of contracting toxoplasmosis, wear gloves while changing cat litter, and thoroughly wash the hands afterward.

Related health problems

A person with advanced HIV or an opportunistic infection may experience complications, including:

HIV-related encephalopathy

progressive multifocal leukoencephalopathy (PML)

wasting syndrome

HIV can trigger encephalopathy, or inflammation in the brain. Doctors do not fully understand the underlying mechanisms.

PML stems from infection with the John Cunningham virus. This virus is present in many people, and it usually lies dormant in the kidneys.

If a person has a weakened immune system — possibly due to HIV or medications such as those for multiple sclerosis — the John Cunningham virus attacks the brain, leading to PML, which can be life threatening and cause paralysis and cognitive difficulties.

Wasting syndrome occurs when a person involuntarily loses 10%Trusted Source of their muscle mass through diarrhea, weakness, or a fever. Part of the weight loss may also involve fat loss.

Associated types of cancer

A person with HIV may have a higher riskTrusted Source of various types of cancer, including lymphoma.

Kaposi’s sarcoma herpesvirus, also known as human herpesvirus 8, causes a type of cancer that involves the growth of abnormal blood vessels. These can develop anywhere in the body.

The cancer is called Kaposi’s sarcoma, and if it reaches organs such as the intestines or lymph nodes, it can be extremely dangerous. On the skin, a doctor may recognize characteristic solid, purple or pink spots, which may be flat or raised.

In addition, Hodgkin and non-Hodgkin lymphoma have strong links to HIV infection. These affect the lymph nodes and lymphoid tissues.

Also, a female with HIV should recieve regular checks for cervical cancer. Receiving an early diagnosis can help limit the cancer’s spread.

Read more about possible complications of HIV here.

Preventing complications

Prevention is key to extending the life of a person with late-stage HIV.

It is important to manage the viral load with HIV medications and take additional precautions, such as:

using condoms to prevent other sexually transmitted infections (STIs)

having vaccinations for potential opportunistic infections

identifying any environmental factors, such as a pet cat, that could lead to infection

limiting exposure to these factors, such as by wearing gloves while changing cat litter

avoiding foods with a high risk of contamination, such as undercooked eggs and meat, unpasteurized dairy and fruit juices, and raw seed sprouts

not drinking water straight from a lake or river or unfiltered tap water in certain countries

asking a doctor about relevant vaccinations and ways to limit exposure to pathogens at work, at home, and on vacation

Antibiotic, antifungal, and antiparasitic drugs can help treat opportunistic infections.

HIV and AIDS myths and facts

Many misconceptions circulate about HIV. These are harmful and stigmatizing.

The following cannot transmit the virus:

shaking hands




touching unbroken skin

sharing a toilet with someone who has HIV

sharing towels

sharing cutlery

mouth-to-mouth resuscitation

anything that might be considered casual contact

touching the saliva, tears, feces, or urine of a person with HIV

Read more myths and facts about HIV and AIDS here.


Data suggest that 1 in every 7 HIV-positive people in the U.S. are unaware of their HIV status.

This awareness is crucial for a person’s health and well-being, as it can enable a person to access the necessary treatment early and prevent complications.

Healthcare professionals can test a person’s blood for HIV antibodies. They will retest the blood before confirming a positive result. Home testing kits are also available.

Current HIV testing platforms make it possible to detect HIV in under 2 weeksTrusted Source. People with known risk factors should undergo testing more often.

Anyone at risk of an infection can have a rapid test. If this is negative, the test provider usually recommends having another test within a few weeks.

The types of HIV test are as follows:

Nucleic acid amplification tests, sometimes called NATs, can detect HIV infection as early as 10 days after exposure.

An antigen or antibody blood test can detect HIV in a blood sample as early as 18 days after exposure.

Most rapid tests and self-tests are antibody tests, and these can detect HIV antibodies as early as 21 days after exposure.

If a person may have been exposed to HIV within the last 72 hoursTrusted Source, they should talk to a healthcare professional about post-exposure prophylaxis (PEP)Trusted Source, a preventive treatment.


While there is no cure for HIV, treatments can stop the progression of the infection.

Receiving these treatments, called antiretrovirals, can reduce the risk of transmission. It can also extend a person’s life expectancy and improve the quality of life.

Many people who take HIV treatments live long, healthy lives. These medications are becoming increasingly effective and well-tolerated. A person may need to take just one pill per day.

The following sections look at HIV treatments and medications for prevention.

Emergency HIV pills: PEP

Anyone who may have been exposed to the virus within the last 72 hoursTrusted Source should speak with a healthcare provider about PEP.

This medication may be able to stop the infection, especially if a person takes it as soon as possible after the potential exposure.

A person takes PEP for 28 days, and a doctor monitors the person for HIV afterward.

PEP is not 100% effective, so it is important to use prevention techniques, such as barrier protection and safe injection practices, including while taking PEP.

Antiretroviral drugs

Treating HIV involves taking antiretroviral medications, which fight the infection and slow the spread of the virus.

People generally take a combination of medications, called highly active antiretroviral therapy or combination antiretroviral therapy. A person might refer to the approach as HAART or cART, respectively.

There are many types of antiretrovirals, including:

Protease inhibitors

Protease is an enzyme that HIV needs in order to replicate. These medications bind to the enzyme and inhibit its action, preventing HIV from making copies of itself.

Types include:

atazanavir and cobicistat (Evotaz)

lopinavir and ritonavir (Kaletra)

darunavir and cobicistat (Prezcobix)

Integrase inhibitors

HIV needs integrase, another enzyme, to infect T cells, and these drugs block the enzyme. Due to their effectiveness and limited side effects, these are often the first line of treatment.

Integrase inhibitors include:

elvitegravir (Vitekta)

dolutegravir (Tivicay)

raltegravir (Isentress)

Nucleoside and nucleotide reverse transcriptase inhibitors

These drugs, also called NRTIs or “nukes,” interfere with HIV as it tries to replicate.

Types include:

abacavir (Ziagen)

lamivudine and zidovudine (Combivir)

emtricitabine (Emtriva)

tenofovir disoproxil (Viread)

Non-nucleoside reverse transcriptase inhibitors

These drugs, called NNRTIs, also make it more difficult for HIV to replicate.

Chemokine coreceptor antagonists

These drugs block HIV from entering cells. However, doctors in the U.S. do not often prescribe them because other drugs are more effective.

Entry inhibitors

Entry inhibitors prevent HIV from entering T cells. Without access to these cells, HIV cannot replicate. They are likewise not common in the U.S.

People often benefit from a combination of antiretroviral drugs, and the right combination depends on factors specific to each person.

The treatment is lifelong and involves taking pills on a regular schedule.

Each class of antiretrovirals has different side effects, but some common ones include:






Complementary or alternative medicine

Many people with HIV try complementary, alternative, or herbal remedies. However, there is no evidence that these are effective.

While mineral or vitamin supplements may benefit health in other ways, it is important to discuss these with a healthcare provider first — some natural products can interact with HIV treatments.


The following strategies can prevent contact with HIV.

Using barrier protection and PrEP

Using a method of barrier protection, such as a condom, during every sexual act can drastically reduce the chances of contracting HIV and other STIs.

In their 2019 guidelines, the Preventive Services Task Force advise that doctors only recommend PrEP to people with recent negative HIV tests.

They also approve a PrEP formation: a combination of tenofovir disoproxil fumarate and emtricitabine. They advise people who take PrEP to do so once a day.

The Food and Drug Administration (FDA)Trusted Source have also approved a second combination drug — tenofovir alafenamide and emtricitabine — as PrEP.

Using safe injection practices

Intravenous drug use is a key means of HIV transmission. Sharing needles and other drug equipment can expose a person to HIV and other viruses, such as hepatitis C.

Anyone who injects any drug should do so with a clean, unused needle.

Needle exchange and addiction recovery programs can help reduce the prevalence of HIV.

Avoiding exposure to relevant body fluids

To limit the risk of exposure to HIV, reduce contact with blood, semen, vaginal secretions, and other body fluids that can carry the virus.

Frequently and thoroughly washing the skin immediately after coming into contact with body fluids can also reduce the risk of infection.

To prevent transmission, healthcare workers use gloves, masks, protective eyewear, face shields, and gowns when exposure to these fluids is likely, and they follow established procedures.


While certain antiretrovirals can harm the fetus during pregnancy, an effective, well-managed treatment plan can prevent transmission to the fetus.

Vaginal deliveries are possible if the person’s HIV infection is controlled well.

It may also be possible for the virus to transmit through breast milk. The Centers for Disease Control and Prevention (CDC)Trusted Source do not recommend breastfeeding, regardless of a person’s viral load and whether they take antiretrovirals.

It is important to discuss all the options thoroughly with a healthcare provider.


Understanding the risk factors is crucial in avoiding exposure to HIV.

Living with HIV

Many people with HIV have long, regular lives. However, due to the risk of damage to the immune system, it is important to adopt the following strategies.

Having a medication routine

Taking HIV medication as prescribed is essential — missing even a few doses might jeopardize the treatment.

A person should design a daily medication-taking routine that fits their treatment plan and schedule.

Sometimes, side effects keep people from sticking with their treatment plans. If any side effect is hard to manage, contact a healthcare provider. They can recommend a drug that is easier to tolerate and suggest other changes to the treatment plan.

Learn more about the adverse effects of HIV medications.

Boosting overall health

Taking steps to avoid illness and other infections is key. People with HIV should get regular exercise, have a balanced, nutritious diet, and avoid unhealthful activities, such as smoking.

It is especially important to prevent exposure to pathogens that cause infection. This migh require a person to stop eating unpasteurized foods and undercooked meats and avoid contact with animal feces and cat litter.

It is also crucial to wash the hands well and regularly.

Overall, antiretrovirals reduce the need for the above precautions.

Staying in contact with doctors

HIV is a lifelong condition, and regularly checking in with a healthcare team can ensure that a person’s treatment is in line with their age and any other health issues. The team will review and adjust the treatment plan accordingly.

Supporting mental health

HIV and AIDS are highly stigmatized and shrouded in misconceptions. As a result, a person may be persecuted, isolated, or excluded.

An HIV diagnosis can be very distressing, and feelings of anxiety or depression are common. Speaking with a mental health professional can help, as can speaking with a trusted doctor.

The CDCTrusted Source provide a list of services that can help people manage the stigma and discrimination and receive additional support.


HIV is a viral infection that reduces the effectiveness of the immune system. Due to advances in treatment, a person with access to quality healthcare who takes antiretroviral medication can lead a long, regular life with HIV.

HIV transmits through some body fluids, such as semen, vaginal secretions, and blood. In the U.S., the most common means of transmission are sharing needles and having sex without barrier protection or a type of preemptive medication called PrEP.

If levels of HIV in the body are so low that a test cannot identify them, a person has an undetectable viral load. In this case, the virus cannot pass from them to someone else. Taking antiretrovirals can help a person achieve this.

If someone with HIV does not receive treatment, possibly because they are unaware of the infection, HIV can progress to a late stage called AIDS.

A person with AIDS is prone to a range of infections and other health issues that can be severe.

Sometimes, HIV causes no symptoms for years or limited symptoms that can be easy to mistake for those of the flu. Anyone in the U.S. who suspects recent HIV exposure can find their nearest testing facility here.