Dr. Justin Coleman, a GP, hosted a podcast featuring Clinical Professor Louise Owen, President of the Australian Chapter of Sexual Health Medicine, to discuss Human Immunodeficiency Virus (HIV) testing guidelines in Australia.
Current HIV Landscape in Australia
Approximately 30,000 individuals in Australia are living with HIV. In 2024, there were 757 new diagnoses. Over the past decade, new HIV diagnoses have seen a 25% reduction, primarily among gay, bisexual, and other men who have sex with men. This decline is attributed to effective prevention strategies, including the widespread adoption of Pre-Exposure Prophylaxis (PrEP) and the principle of 'treatment as prevention,' where individuals on effective treatment with an undetectable viral load cannot transmit the virus sexually.
Currently, an estimated 92% of people living with HIV in Australia are aware of their status, 97% are on treatment, and 98% of those on treatment have an undetectable viral load. Efforts are focused on identifying the remaining 8% who are unaware of their HIV status to ensure early diagnosis and treatment, which can lead to a near-normal life expectancy.
Populations Recommended for HIV Testing
Universal HIV testing is not applied in Australia due to lower prevalence compared to some other countries. Testing is concentrated in specific populations:
- Antenatal Screening: Universal testing is recommended for all pregnant individuals, including at least three syphilis tests per pregnancy.
- STI Screening: HIV and syphilis testing are part of routine screening for all epidemiological risk groups. Guidelines are available on Australianstiguidelines.org.au.
- High-Risk Groups: This includes individuals who inject drugs, those who have been incarcerated, or people who have traveled to or had risk behaviors with individuals from high-prevalence countries.
- PrEP Patients: Individuals on PrEP are recommended to undergo STI testing, including HIV, every three months.
- Healthcare Workers: Practitioners performing procedures involving sharps in body cavities, where visibility is limited, are advised to be aware of their HIV status.
HIV Indicator Conditions
Testing for HIV is recommended when specific 'indicator conditions' are present, particularly if HIV prevalence in the population is estimated at 0.1% or higher. These conditions fall into three categories:
AIDS-Defining Illnesses
These include severe conditions such as:
- Pneumocystis pneumonia
- Cervical cancer
- Kaposi sarcoma
- Hodgkin lymphoma
- Oesophageal candidiasis
Non-Specific Conditions Potentially Caused by HIV
These are more commonly encountered in general practice and may not immediately suggest HIV, but warrant testing:
- Unexplained weight loss or diarrhea
- Thrombocytopenia
- Multidermatomal shingles
- Recurrent bacterial pneumonia
- Any sexually transmissible infection (STI)
- Diagnosis of hepatitis B or C
Pre-Treatment Workup
HIV testing is recommended as part of a standard workup for patients about to receive systemic chemotherapy or immune-modulating therapies.
HIV Testing Procedures
- Standard Serology: General practitioners typically request an HIV serology test. Laboratories use fourth or fifth-generation tests that detect both antibodies and antigens.
- Window Period: Early infection (window period) may not be detected immediately. Retesting is recommended 6-12 weeks after a potential exposure.
- Point-of-Care Rapid Tests: These are useful screening tools, often used by healthcare workers in remote or outreach settings. Any reactive result requires confirmation with a laboratory serological test.
- Rapid Self-Testing: Available for home use, these tests also require clinical follow-up and confirmation if reactive.
Interpreting Results
- Negative Result: Considered highly accurate, but clinicians should assess the clinical context, including the window period and ongoing risk, for potential retesting.
- Positive Result: An initial reactive screening test (e.g., ELISA) is followed by more sensitive and specific confirmatory tests (e.g., Western blot, RNA test). A conclusive positive result indicates HIV infection. In such cases, the laboratory automatically notifies public health authorities and typically contacts the ordering clinician. Support from local sexual health or infectious diseases services is available to link patients to care and ensure prompt initiation of antiretroviral treatment, which is provided free of charge in Australia, including for those without Medicare.