HIV and AIDS | Causes & Risk Factors


How can I get HIV?

HIV can only be passed from person to person through body fluids, such as blood, semen and vaginal fluid. Children born to infected mothers can also become infected during pregnancy. The most common ways HIV is passed are:

  • By having unprotected anal, vaginal or oral sex with an infected person.
  • By sharing needles and syringes for injecting drugs with an infected person.

More than half of women who have HIV got the infection from sexual partners. A woman can be infected by contact with a man or contact with another woman. When a woman has sex with an infected man, she has a high risk of getting HIV if a condom is not used properly.

Who is at risk for HIV infection?

In the early days of the AIDS epidemic, HIV infection appeared to be confined to certain groups, including intravenous drug users, men who have sex with other men and persons who have hemophilia (a blood-clotting disease that requires treatment with frequent blood transfusions). People who have hemophilia got HIV from receiving blood transfusions with donated blood that contained HIV. Blood donations are now tested for HIV, and HIV-infected blood donations are destroyed.

These days, HIV infection is much more widespread. Here is a list of people who are at high risk of HIV infection:

  • Men who have sex with other men.
  • Anyone who has multiple sex partners.
  • Anyone who has sex with a prostitute.
  • Anyone who shares needles using illegal injected drugs.
  • Anyone who exchanges sex for drugs or money.
  • Anyone who has a sexually transmitted disease.
  • Anyone who has had or currently has a sexual partner with any of the above risk factors.

How do babies get HIV from their mothers?

Babies can get HIV infection from their mothers during pregnancy, during the birth process and during breastfeeding.

It is now possible to prevent many cases of HIV in children by giving medicines to the pregnant mother and to her newborn baby. This protection cannot be offered if a pregnant woman does not know she is infected. Many people who have HIV infection feel perfectly healthy at first. The only way to know if you are infected is to have an HIV test. If you are pregnant, ask your doctor for an HIV test as part of your prenatal care. Better yet, if you are thinking about getting pregnant, talk to your doctor about HIV tests for you and your partner.

What contact is safe?

HIV can't live very long outside the body, so you can't get it through casual contact. You can't get the virus by touching, shaking hands, hugging, swimming in a public pool, giving blood, or using hot tubs, public toilets, telephones, doorknobs or water fountains. You also can't get it from food, mosquitoes or other insects.


How to Recognize and Treat Acute HIV Syndrome by BL Perlmutter, M.D., Ph.D., JB Glaser, M.D., and SO Oyugi, M.D. (American Family Physician August 01, 1999,

Written by editorial staff

Reviewed/Updated: 04/14
Created: 01/96