HIV is a virus that targets the body’s immune system, reducing its ability to fight off infections and disease. Without treatment, HIV can progress to AIDS and lead to other complications across the body.

Around 1.2 million people in the United States are living with HIV, and an estimated 1 in 7 people with HIV do not know they have it.

With treatment, many people with HIV can considerably reduce their risk of complications and have a life expectancy comparable to people without HIV.

Without treatment, however, HIV infection eventually progresses to advanced HIV, also known as AIDS. Having untreated HIV can put a person at risk of several complications, including the development of certain rare infections and cancers.

In this article, we list the most common HIV complications and explain how treatment can prevent their onset.

A collection of blood samples. A scientist's gloved hand is picking up a vial of blood.Share on Pinterest
Getty Images

When a person first contracts HIV, they often experience an initial period of flu-like symptoms within 2–4 weeks of infection, known as acute HIV.

After this, they may experience no symptoms for many years, known as chronic HIV. This stage can last for 10 years or more without treatment, or be life-long with treatment, although this is rare.

Without treatment, HIV can progress to advanced HIV or AIDS. People with AIDS are more susceptible to several types of infection, known as opportunistic infections, as well as some cancers.

HIV gradually targets specific immune system cells called CD4 cells. Over time, the virus damages more and more of these cells until the immune system is not strong enough to fight off infections.

If the CD4 count of a person living with HIV falls below 200 cells per cubic milliliter (cells/mm3), or if they develop an opportunistic infection, the person is said to have AIDS.

Complications arise when a person’s CD4 cell count becomes very low. The person is more likely to develop infections, certain types of cancer, and other medical complications.

Opportunistic infections are illnesses that are typically mild in people without HIV, but arise more often and are more severe in people with HIV if they have a damaged immune system.

Because people living with HIV in the U.S. widely use HIV drugs, fewer people now get opportunistic infections.

Common opportunistic infections for people living with HIV include the following:

Herpes simplex virus

Herpes simplex virus is a common virus that affects many people, occasionally causing sores around the mouth or genitals.

For people with HIV, it can be especially problematic and lead to recurrent sores.

It may cause infections in the bronchus (breathing tube) or the esophagus (the tube that connects the mouth and stomach). It can also lead to pneumonia.


This fungal infection causes a thick, white coating to form on the skin, nails, and mucous membranes.

Candidiasis commonly affects the mouth, vagina, and esophagus. When it affects the vagina, it is called a vulvovaginal yeast infection. When it affects the mouth, it is known as oral thrush.

Medical professionals consider this to be an opportunistic infection when it causes severe or persistent infection in the mouth or vagina, or when it occurs in the esophagus.

Salmonella septicemia

Infection with the Salmonella bacteria causes approximately 1.35 million illnesses in the U.S. every year. Contaminated food is the primary cause.

For people with HIV, a Salmonella infection may progress to a severe form called Salmonella septicemia that spreads to the bloodstream.


Cats, rodents, and other animals often carry the Toxoplasma gondii parasite. When transmitted to humans, it can affect many body parts, including the eyes, lungs, heart, and liver.

If it reaches the brain, toxoplasmosis can cause seizures.

A person with a weakened immune system may develop toxoplasmosis if they come into contact with cat litter or other sources of animal feces. It can also develop after a person eats undercooked red meat or pork.


Pneumonia is a lung condition that results from an infection by one of many bacteria, viruses, or fungi. It can be severe or life-threatening for people with HIV.

Symptoms of pneumonia include:

  • chills
  • difficulty breathing
  • fever
  • a wet or productive cough

A vaccination for a particularly severe form of bacterial pneumonia (pneumococcal pneumonia) is available to prevent infection. Anyone with HIV should discuss the benefits of this vaccine with their doctor.


Tuberculosis is a bacterial infection of the lungs but may spread to other parts of the body, including the kidneys, spine, and brain. It can lead to symptoms such as:

Worldwide, tuberculosis is one of the leading causes of death in people with HIV. It is less common in the U.S. than it was in the past due to the availability of HIV medication, but it still affects many people with HIV.


A fungal infection that usually affects the lungs, coccidioidomycosis results from inhaling fungal spores that are common in hot, dry regions, such as the southwestern U.S.

It causes a form of pneumonia called desert fever.


This fungal infection enters the body through the lungs, leading to pneumonia. It can then spread to the brain, where it causes meningitis and swelling.

It can also affect the bones, skin, and urinary tract.


People can contract cryptosporidiosis by eating or drinking food or water contaminated with the intestinal parasite Cryptosporidium. It causes severe and persistent diarrhea.


Cytomegalovirus (CMV) is a viral infection that can cause:

  • brain inflammation, known as encephalitis
  • inflammation in the retina of the eye, called retinitis
  • an inflamed stomach, or gastroenteritis


The fungus Histoplasma capsulatum typically infects the lungs, causing histoplasmosis, a type of pneumonia.

People with advanced HIV may be more likely to develop a severe form of histoplasmosis that affects other organs too.


Eating contaminated food or water can cause an isosporiasis infection. In those with HIV, symptoms of isosporiasis can be severe and include:

  • diarrhea
  • fever
  • vomiting
  • weight loss

Mycobacterium avium complex

Different types of mycobacteria cause mycobacterium avium complex (MAC) infection, which rarely affects people without HIV.

In those with HIV, especially advanced HIV, this bacterial infection can be life-threatening. It can cause pneumonia or spread throughout the body.

Pneumocystis jiroveci pneumonia

Pneumocystis jirovecii pneumonia, or PJP, is a fungal lung infection that causes:

  • breathing problems, including low oxygen
  • a dry cough
  • fever

Progressive multifocal leukoencephalopathy

This is a rare viral condition that affects the brain and spinal cord. It predominantly affects people with HIV.

Symptoms include:

  • blindness
  • mental impairment
  • paralysis

HIV and AIDS resources

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

Was this helpful?

People with advanced or uncontrolled HIV are more likely than people without HIV to develop several types of cancer, including the following:

Kaposi sarcoma

Kaposi sarcoma is rare in people who do not have HIV. It causes tumors in the walls of the blood vessels that appear as pink, purple, or black lesions on the skin.

If Kaposi sarcoma spreads to the lungs, lymph nodes, gastrointestinal tract, or other organs, it can be life-threatening.

Invasive cervical cancer

Cervical cancer begins in the cervix, which is the bottom section of the uterus. Without treatment, it can spread to nearby organs and other areas of the body.

Regular cervical checks and pap smears can help prevent the development and progression of cervical cancer.


There are many forms of lymphoma, which are cancers that affect the white blood cells and lymph nodes.

One early symptom is swelling of the lymph nodes. Types that often affect people with HIV are Hodgkin lymphoma and non-Hodgkin lymphoma.

People may also develop coinfections. This is where more than one infection is active at the same time.

Common coinfections with HIV include:

People can contract hepatitis B and C in similar ways to HIV, such as through sex or shared drug injection equipment.

Around 10% of people in the U.S. with HIV also have hepatitis B, and around 25% of people with HIV also have hepatitis C.

An HIV diagnosis can have a significant impact on a person’s mental health.

Living with HIV introduces various forms of stress, such as having to coordinate medical support, manage medications, and deal with the unfair stigma associated with HIV.

People living with HIV are twice as likely to have depression. There is also an increased risk for other mood, anxiety, and cognitive disorders.

Talking therapies, social support, medications, and other treatments can help many people deal with the mental health impact of HIV.

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

Though the reason isn’t clear, HIV is associated with certain neurocognitive disorders later in life, even when taking effective treatment.

These are known as HIV-associated neurocognitive disorders (HAND), and can range from occasional memory loss to dementia.

Some people with advanced HIV develop wasting syndrome. This is a loss of at least 10% of their body weight along with diarrhea, fever, or weakness for at least 1 month.

HIV and some drugs that treat HIV may increase a person’s risk of heart disease or kidney disease.

The best way to prevent complications from HIV is to take medication consistently as prescribed, and to start treatment as soon as possible.

Antiretroviral therapy keeps the immune system healthy and, when taken consistently so that the level of HIV virus in the blood is undetectable, reduces the risk of transmitting the virus to others to zero.

The following lifestyle habits may also help people with HIV stay healthy:

  • Eating a balanced diet, full of fresh fruits and vegetables, whole grains, and lean protein sources.
  • Avoiding raw meat, seafood, eggs, and unpasteurized dairy products, as they may increase the risk of food poisoning.
  • Preparing and storing food in a hygienic manner.
  • Not drinking water directly from lakes or rivers.
  • When abroad, drinking bottled water and avoiding ice and foods that may be a source of infection, such as raw meat or peeled fruits and vegetables.
  • Always using condoms and other barrier methods when having sex to avoid getting other STIs.
  • Never sharing needles or syringes with anyone else.
  • Avoiding people who have contagious infections.
  • Avoiding some supplements, such as St. John’s wort and garlic supplements, which may interfere with antiretroviral medications.
  • Practicing good hygiene around pets, especially cats, and their feces. Wear gloves when changing litter trays and wash hands thoroughly afterward.
  • Asking a doctor about vaccinations to help prevent pneumonia and other serious infections.

Many effective medications are available to treat HIV symptoms and prevent the virus from progressing to AIDS.

When a person receives antiretroviral treatment, it reduces their viral load. The viral load is the amount of virus in a person’s blood or fluids. When a person’s viral load becomes undetectable, it means that they can no longer transmit the virus to other people.

Healthcare providers recommend that everybody with HIV begin antiretroviral medications as soon as possible, regardless of their age, symptoms, or CD4 cell count.

Treatments are most effective when the person takes them consistently as prescribed by the doctor, and goes for regular health checkups.

Treatments for opportunistic infections include antiviral drugs, antibiotics, or antifungal drugs.

Although people with HIV are at risk of a range of complications, the outlook for those with the condition has improved drastically over the last few decades. Modern treatments can prevent both symptoms and complications from developing.

Together with lifestyle changes, antiretroviral medications mean that most people with HIV can have a lifespan similar to that of the general population.