How is HIV Transmitted?

HIV is transmitted through body fluids such as blood, semen, vaginal fluid, breast milk and other fluids containing blood.

The virus is most commonly transmitted in the following ways:

• having unprotected (not using condoms) vaginal or anal sex with an infected person
• through pregnancy, labour or breastfeeding from HIV-infected mother to child if the mother is not on treatment(see Prevention Factsheet: Prevention of Mother-to-Child Transmission)
• infected blood received during blood transfusion where either the blood has not been screened for the virus, or unsterilised needles have been used (see Prevention Factsheet: Blood Screening)
• sharing needles for intravenous drug use with an infected person

The virus can also be transmitted via oral sex as body fluids can be transferred through cuts or sores around or in the mouth or throat. The risk of HIV-transmission through oral sex is extremely low.

No evidence has been found that the virus can be transmitted through kissing (unless intraoral bleeding occurs), saliva, tears, sweat, or via insects (such as mosquitoes). Read the US Centers for Disease Control (CDC) Facts on the spread of HIV.

Additional resources: