What is the HIV status of the source individual?

Provision of PEP should not be delayed while establishing the source status.

Ideally, active attempts should be made to contact the source and ask them to have an urgent HIV test; however, the often anonymous nature of exposures makes this impractical.


  • If the source cannot be contacted, the seroprevalence data (see Table 2) will assist in determining the need for PEP.
  • If the source is contactable and:
    • discloses they are HIV positive, consent should be gained to seek treatment details from their doctor. It is useful to know if they are on treatment or not, and if their viral load is undetectable.
    • is known to be taking PrEP (Pre-Exposure Prophylaxis), PEP is generally not required. Decisions to prescribe PEP should still be considered on a case-bycase basis due to potential for non-adherence of the source.
    • chooses not to disclose their HIV status or have an HIV test, it should be assumed (for the purposes of PEP prescription) that they are HIV positive.

Table 2. HIV seroprevalence in Australian populations

See Literature Review1 section HIV status of the source individual for further information.

Community group HIV seroprevalence (%) Estimated risk of HIV
Men who have sex with men (MSM)8-13
  • ACT
  • Adelaide
  • Queensland
  • Melbourne
  • Perth
  • Sydney
Actual seroprevalence may be higher than reported seroprevalence14
People who inject drugs in Australia15
  • MSM
  • all others

Heterosexuals in Australia16
  • new blood donors (% donations)
  • sexual health clinic attendees

Female commercial sex workers (Australia)15  <0.1
Overall Australian seroprevalence15 0.14

HIV seroprevalence in overseas populations

The seroprevalence overseas varies widely, with a High Prevalence Country (HPC) being defined as having a prevalence of >1% in the general population. However, variance is not only between countries but also in different risk groups. Highest seroprevalence is in Southern Africa (up to 26%) and in people who inject drugs in South East Asia (up to 40% in Thailand and Indonesia). For seroprevalence for individual countries go to http://aidsinfo.unaids.org/