Last Updated June 2023 | This article was created by editorial staff and reviewed by Kyle Bradford Jones, MD, FAAFP

What is AIDS?

AIDS (acquired immune deficiency syndrome) is the last stage of the life-threatening human immunodeficiency virus (HIV) that makes your body’s cells unable to fight off infections. Having it makes you more susceptible to the serious consequences of infections and other diseases. Essentially, AIDS attacks your body’s immune system, killing CD4 cells (also called T cells). If HIV is left untreated, it will continue to kill off CD4 cells your body needs to fight off infections. When this happens, it is considered stage 3 HIV, or AIDS.

It is important to note that treatment options have come a long way for HIV/AIDS, making it more of a chronic disease than a fatal one. However, once you have been diagnosed with HIV, you cannot cure it. It requires a lifetime of management.

Symptoms of AIDS

AIDS symptoms are triggered by the body’s weakened immune system. This means that if you have AIDS, your body can’t fight off infections and other conditions. People who have AIDS are at high risk of getting opportunistic infections. These infections can be caused by bacteria, viruses, fungi, etc. They can affect any part of the body. AIDS also puts you at higher risk for certain cancers, especially lymphomas, skin cancer, and cervical cancer, according to the National Institutes of Health.

AIDS symptoms will vary, but may include:

  • Lung infections (cough, fever, and shortness of breath)
  • Intestinal infections (diarrhea, abdominal pain, and vomiting)
  • Extreme tiredness
  • Swollen lymph glands
  • Mouth sores
  • Fever
  • Sweats
  • Rashes or skin lesions
  • Weight loss

What causes AIDS?

AIDS is caused by HIV, a virus. HIV is spread from person to person several ways. You can get HIV by having sexual contact with a person who has HIV. You can also get it if you share a needle with someone who has HIV. Pregnant mothers who have HIV may pass it to their babies during pregnancy, childbirth, or while breastfeeding.

How is AIDS diagnosed?

When you have HIV, your doctor will monitor your CD4 count by ordering a blood test. A healthy CD4 count ranges from 500 to 1,600 CD4 cells. The lower your CD4 count, the less your body can fight infection. If your CD4 count drops below 200, your doctor may diagnose you with AIDS. Many times, you will also already have an infection or pneumonia due to the low number of CD4 cells.

Can AIDS be prevented or avoided?

You can prevent AIDS by preventing HIV. The best way to prevent HIV is to not have sex (vaginal, anal, or oral) with a person who has HIV, or share a needle with a person who has HIV.

Other ways to prevent HIV include:

  • Use a condom when you have sex. The best condom is a male latex condom. A female condom isn’t as effective but does offer some protection.
  • Don’t share needles and syringes.
  • Never let someone else’s blood, semen, urine, vaginal fluid, or feces get into your anus, vagina, or mouth.


Even though there is no cure for HIV, there are many medicines available to help combat it. These medicines (called antiretroviral therapy or ART) will often prevent HIV from progressing to AIDS. Even when HIV does progress to AIDS, ART is often still effective. However, it’s most effective the earlier you begin treatment.

One HIV preventive medicine is known as PrEP (pre-exposure prophylaxis). This is a medicine for people who are at high risk of contracting HIV from sex or drug use. When taken as prescribed, PrEP is highly effective for preventing HIV, according to the Centers for Disease Control and Prevention.

Another HIV medicine, known as PEP (post-exposure prophylaxis) is effective when taken 72 hours after a possible exposure to HIV. It is designed to prevent the virus from taking hold. However, when taking both these medicines, the virus can still be transmitted through sex and drug use.

Living with AIDS

Without treatment, the survival rate for someone with AIDS is about 3 years. That number decreases if they get an infection or cancer as a result of their weakened immune system.

With treatment, though, the survival rate for HIV and even AIDS is much better. In the United States, most people with HIV don’t develop AIDS because effective ART stops disease progression.

Questions to ask your doctor

  • When should I begin taking antiretroviral medicine?
  • How will you decide which medicine I should take?
  • Are there lifestyle changes I should make to stay healthy?
  • How can I protect my partner during sex?
  • How can I protect myself from opportunistic infections?


Centers for Disease Control and Prevention: About HIV/AIDS

Centers for Disease Control and Prevention: PrEP (pre-exposure prophylaxis) 

Centers for Disease Control and Prevention: What is PEP?

National Institutes of Health, MedlinePlus: HIV/AIDS



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