HIV prevention basics

How is HIV transmitted? 

HIV does not live for long outside of the body and can only be transmitted (passed from one person to another) through certain bodily fluids.  

The fluids which can contain enough HIV virus for transmission to occur are: 

  • blood, 
  • semen (cum), 
  • pre-seminal fluid (pre-cum), 
  • rectal fluids, 
  • vaginal fluids, and 
  • breast milk. 

Transmission can only happen if there is a point where these fluids can leave the body of a person living with HIV and come into direct contact with entry points inside the body of an HIV negative person. There must also be a detectable amount of virus in the bodily fluids of the person living with HIV.  These conditions need to exist for HIV transmission to occur.  

HIV cannot be spread through saliva.  

In Australia, the main ways that HIV is transmitted are anal and vaginal sex. During sex, some of these bodily fluids come into contact with entry points such as mucous membrane or damaged tissue in the anus, vagina or penis. Either the insertive or receptive partner may be at risk. HIV can also be passed on through sharing injecting drug equipment, such as needles and syringes. When a needle or syringe is shared, blood is injected directly into the blood stream.  

HIV can be transmitted from parent to child during pregnancy, child birth and breastfeeding. Parent to child transmission is now rare in Australia due to the availability of effective HIV treatments and prevention practices.  

There are other ways that HIV could be transmitted but these happen very rarely in Australia.  The risk of HIV transmission during oral sex almost non-existent. Additional factors, such as an open wound and ejaculation into the mouth during oral sex would need to occur for HIV transmission to be possible.  HIV transmission has occurred from contact with contaminated sharp objects, as well as medical procedures such as blood transfusions. Standard precautions for infection control and disease prevention means that HIV transmission does not occur in healthcare and workplaces in Australia. 

HIV cannot be spread through everyday activities such as holding hands, hugging or sharing space with an HIV positive person.  

Ways of preventing HIV 

There are many effective ways to prevent HIV. When it comes to choosing, your best HIV prevention methods are ones that work for you and your partners.  

Condoms create a physical barrier that prevents the transmission of HIV during sex. Condoms must be fitted and used properly with lubrication to ensure that they do not slip or tear. When used correctly condoms are an effective, cheap and accessible way to prevent HIV. Condoms can also be used when the HIV status of either partner is unknown. You can find detailed information about how to use condoms by visiting the websites of Ending HIV or Sexual Health Victoria.   

When injecting drugs, not sharing equipment or using new or clean equipment will prevent the transmission of HIV. For detailed information about safe injecting drug use visit the website of the Australian Injecting and Illicit Drug Users League (AIVL: https://aivl.org.au/) 

Reducing the amount of virus in the bodily fluids of a person living with HIV to undetectable levels can further reduce the risk of sexual transmission to zero.  HIV treatments are highly effective at stopping the virus from replicating and can be used by HIV negative and positive people to prevent transmission even when condoms are not used. Refer to Treatment as Prevention for more information.