How is HIV transmitted?

To be infectious HIV must be present in body fluids in large quantities. HIV is only in such large quantities in blood, semen, pre-ejaculatory fluid (‘pre-cum’), anal mucus, vaginal secretions and breast milk of an HIV-positive person. A person can only become infected if one of these body fluids enters their blood stream. In Australia the main ways in which this happens are:

Oral sex is very low risk for HIV transmission. There are no reliable reports of anyone getting HIV from oral sex on a woman with HIV, and only a few reports of HIV transmission resulting from oral sex between men. More info here.

An HIV-positive woman can transmit HIV to her child during pregnancy, birth or via breastfeeding. There are a number of ways to minimise the risk of HIV transmission, including antiretroviral therapy, caesarean delivery and avoiding breastfeeding. Taking these precautions reduces the risk of mother to child transmission risk to around 1 to 2 percent. Mother to child transmission (sometimes referred to as ‘vertical transmission’) is now rare in Australia.

See also: Mother to Child Transmission

A small number of people working in healthcare have been infected with HIV through workplace exposure to body fluids, for example through ‘needlestick’ injuries, where their skin has been pierced by a needle containing HIV infected blood.

In over 30 years of HIV in Australia there has not been one report of HIV transmission as a result of accidental injury with discarded hypodermic needles outside of a hospital setting , e.g., from stepping on a discarded syringe.

(See also Stories about HIV exposure risk in the community)

In some countries blood supplies for transfusions and other blood products can also be a source of transmission; however, the Australian blood supply is regarded as safe.

In Australia blood donations are managed by the Australian Red Cross Blood Service, which is responsible for ensuring the safety of the blood supply for transfusions and other medical treatments. Since 1985 Australian blood donations have been screened for HIV.