Anti-viral therapy to prevent HIV: TasP, PrEP and PEP

Treatment as prevention (TasP)

In addition to the use of condoms with lubricant, antiretroviral therapy (ART) is available to prevent HIV from being transmitted from one person to another.

Research shows that the use of treatment as prevention (TasP) is very effective in preventing HIV transmission, i.e. people living with HIV who are on ART and have an undetectable viral load, are very unlikely to transmit HIV to their sexual partners.

PrEP and PEP

In addition to TasP, pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP) are available. PrEP is taken on a daily basis to prevent HIV infection in individuals who are at ongoing risk of getting HIV. PEP is a 28-day course of medication taken after a possible exposure to HIV.

Further information about both PrEP and PEP is provided in the table below.

Table 1: PrEP and PEP for HIV

Pre-exposure prophylaxis (PrEP) Post-exposure prophylaxis (PEP)
What is it? PrEP is daily medication to prevent HIV infection in people who are HIV-negative and at ongoing risk of getting HIV PEP is a 28 day course of medication to prevent HIV infection in people who are HIV negative and have experienced a single event where they have had a known, or possible, exposure to HIV
Who is eligible? People who are HIV-negative and likely to be experiencing multiple events where there is a risk of HIV exposure, e.g. having unprotected sex and/or sharing injecting equipment with someone who has HIV or is at high risk of having HIV; or being in a relationship with a HIV-positive person who has a detectable viral load People who are HIV negative and who have experienced a single event, e.g. unprotected sex (including condom breakage) and/or shared injecting equipment, with someone who has HIV or is at high risk of having HIV
How is it accessed? A Government-funded PrEP trial is now available in WA for people at high risk of HIV. For more information see PrEP IT WA (external site) website. 
PrEP can be prescribed by a HIV s100 prescriber, however it is not currently funded by the PBS. Patients can either pay for Truvada® from a pharmacy or import generic versions. See the National PrEP Guidelines (external site) and Interim PrEP Guidelines for WA (external site) for more information
Patients should be encouraged to call the PEP Line (1300 767 161), where they will be risk assessed by trained staff and given advice and, if necessary, a referral.
When should it be taken? Every day As soon as possible, but definitely within 72 hours of exposure

This information is available as a business card sized leaflet, which can be given to patients who may be at high risk of HIV. To obtain copies of this leaflet, please contact

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