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How Do People Get AIDS?

Reviewed by: Robyn R. Miller, MD

What Is HIV?

HIV (human immunodeficiency virus) is a that attacks the immune system. AIDS (acquired immune deficiency syndrome) happens after someone has had HIV for many years. In AIDS, the immune system is severely weakened. People with AIDS get serious infections and health problems.

How Does HIV Spread?

HIV spreads when infected blood, semen ("cum") or vaginal fluids enter the body. Because symptoms can be mild at first, people with HIV might not know they're infected. They can spread HIV to others without knowing it.

HIV can spread:

  • during sex (especially anal sex and vaginal sex)
  • through sharing needles for injecting drugs or tattooing
  • by getting stuck with a needle with an infected person's blood on it

HIV also can pass from mother to child during pregnancy, childbirth, or breastfeeding.

HIV does not spread through:

  • pee, poop, spit, throw-up, or sweat (as long as no blood is present)
  • coughing or sneezing
  • holding hands
  • sharing eating utensils or drinking glasses

How Can I Protect Myself?

The best way to protect yourself from HIV is to not have sex (vaginal, oral, or anal) and not share needles.

If you decide to have sex, reduce your risk of getting HIV by:

  • using a condom every time you have sex (including vaginal, oral, or anal sex)
  • getting tested for HIV and making sure all partners do too
  • reducing the number of sexual partners you have 
  • getting tested and treated for STDs (sexually transmitted diseases); having an STD increases the risk of HIV infection

Understanding how HIV spreads can help you make safer choices about sex. Talk to your doctor if you have any questions about HIV and if you want to get tested.

Reviewed by: Robyn R. Miller, MD
Date reviewed: October 2018