What is the human immunodeficiency virus (HIV)?
The human immunodeficiency virus (HIV) is a type of virus called a retrovirus. It causes AIDS (acquired immunodeficiency syndrome), which is life-threatening.
HIV is called an immunodeficiency virus because it weakens (causes deficiency) of your immune system. Your immune system Overview of the Immune System The immune system is your body's defense system. It helps protect you from illness and infection. The immune system's job is to attack things that don’t belong in your body, including: Germs... read more helps defend you against infection and cancer.
HIV infection weakens your immune system because it kills certain types of white blood cells called CD4 lymphocytes. Without enough CD4 lymphocytes, you're more likely to get certain infections and cancers.
HIV infection weakens your body's defenses against certain infections and cancers
There's no cure for HIV, but HIV medicines make a big difference in slowing down the virus
Without treatment, HIV causes AIDS
Starting HIV medicines as soon as you can may help you avoid AIDS-related problems
People don’t die from HIV itself, but from complications of the infections and cancers they get
Practicing safe sex, not sharing needles, and not getting other people's blood on you help prevent HIV infection
What is acquired immunodeficiency syndrome (AIDS)?
AIDS is acquired immunodeficiency syndrome caused by HIV. Not everyone with HIV infection has AIDS. You have AIDS when you have HIV infection along with either:
A very low number of CD4 lymphocytes
Certain infections and cancers
There are many infections and cancers that define AIDS. Some common ones include:
Fungal infections of your esophagus (the "food pipe" that connects your throat and your stomach), brain, or lungs
Kaposi sarcoma Kaposi Sarcoma Kaposi sarcoma is a skin cancer that causes multiple flat pink, red, or purple patches or bumps on the skin. It is caused by human herpesvirus type 8 infection. One or a few spots may appear... read more , a cancer that causes painless red or purple blotches on your skin or inside your mouth
Certain infections that a healthy immune system can fight off but a weak one can't, such as pneumocystis pneumonia Pneumonia in People With a Weakened Immune System Pneumonia is infection of the lungs. Pneumonia in people whose immune system is weakened or impaired (for example, by human immunodeficiency virus [HIV], cancer, organ transplantation, or the... read more , toxoplasmosis Toxoplasmosis Toxoplasmosis is infection caused by the protozoan parasite Toxoplasma gondii. Infection occurs when people unknowingly ingest toxoplasma cysts from cat feces or eat contaminated meat... read more , and cytomegalovirus Cytomegalovirus (CMV) Infection Cytomegalovirus infection is a common herpesvirus infection with a wide range of symptoms: from no symptoms to fever and fatigue (resembling infectious mononucleosis) to severe symptoms involving... read more
People with AIDS often have severe weight loss—this is called "AIDS wasting."
What causes HIV infection?
When the HIV virus takes over a CD4 lymphocyte, it makes many copies of itself before killing the CD4 cell and releasing the virus copies. Those copies then take over other CD4 lymphocytes, which make even more copies. This cycle continues until there are billions of HIV viruses in your body.
You can be infected with HIV from contact with the body fluids of an infected person, especially:
It’s rare to get infected from someone's tears, urine, or saliva. These fluids carry the virus but in smaller amounts.
You can get HIV by having unprotected sex with an infected person
You can get HIV by sharing needles with an infected person
Children can get HIV Human Immunodeficiency Virus (HIV) Infection in Children Human immunodeficiency virus (HIV) is a virus that affects the body's immune system. People with HIV are more likely to get sick with other infections and illnesses. Young children who have... read more from infected mothers during pregnancy, childbirth, and breastfeeding
But you can’t get HIV by touching, holding, or being near someone with HIV
What are the symptoms of HIV?
Many people have no symptoms right away. Within 1 to 4 weeks after getting HIV, you may have symptoms like:
Lumps in your neck, under your arms, or in your groin—the lumps are swollen lymph nodes, tiny bean-shaped organs that help your body fight infection
Feeling weak and tired
These symptoms last 3 to 14 days. After these go away, you may have few or no symptoms for years.
Later on, if you aren't treated, your weakened immune system has trouble protecting you from infections. You'll have different symptoms depending on what infection you get. For example, with a lung infection, you may have a cough and trouble breathing. With an infection in your esophagus, you may have pain when you swallow. An infection in your intestines will cause diarrhea and weight loss.
How can doctors tell if I have HIV?
Doctors first do a simple screening test on your blood or saliva (spit). If the screening test shows signs of HIV, doctors do other blood tests to tell for sure.
If you have an HIV infection, doctors measure the amount of HIV in your blood.
This amount is called the viral load
The viral load is an important number for you and your doctor. A high viral load is bad. It means there's a lot of virus in your body and your immune system is very weak. A low viral load is good. It usually means your treatment is working.
Doctors also regularly do blood tests to see how many CD4 cells you have.
This is called your CD4 count
A high CD4 count means your immune system is strong. A low CD4 count means your immune system is getting weaker. A low CD4 count may mean your drugs have stopped working or you aren't taking them. The drugs may stop working because the virus has developed resistance to them. When your CD4 count gets very low, you may have to take medicine to prevent infections.
Knowing you have HIV is important because getting treatment can help you live longer, be healthier, and not pass on the virus to other people.
How do doctors treat HIV?
Doctors can’t cure your HIV, but they can use HIV medicines, called antiretroviral medications, to slow down the infection:
Antiretroviral medications stop HIV from copying itself and lower the amount of HIV in your blood
You usually take 3 or more different HIV medicines because HIV medicines work best in groups
Often several medicines are put into one tablet, so you don't have to take as many pills
HIV medicines must be taken for life
If you stop taking the medicine, even for a short time, the HIV can come back
If you take your medicine exactly as the doctor prescribes, you can live a long time with HIV infection.
Doctors may give you other medicines to:
Prevent other infections, such as thrush and pneumonia
Help with side effects, such as weakness and weight loss
Make sure all of your doctors know which HIV medicines you’re taking before they give you any other medicines.
How can I prevent HIV?
You can prevent HIV by practicing safe sex and not sharing needles.
Use a latex condom during sex and use the condom correctly so it's less likely to leak or break
Don’t use petroleum jelly or another oil-based lube with condoms because it can weaken them
Get tested for HIV and ask your partner to get tested too before ever having any type of sex together
Don’t share needles or syringes with anyone
Wear latex gloves if you might come into contact with the blood or other body fluids of another person
If you're pregnant, get an HIV test so your doctor can start you on medicine to prevent your baby from getting infected
You can also take HIV medicines before being exposed to HIV, called preexposure prophylaxis (PrEP). But the medicines are expensive and are usually only prescribed for people with a high risk of infection, such as people who have a partner with HIV.
If you already have HIV, you can prevent the spread of infection to other people by practicing safe sex and not sharing needles.
There isn't yet a vaccine to prevent HIV infection.