Question

Can I test and use drugs immediately after exposure?

21 September 2007. Related: All topics, HIV testing, HIV transmission, PEP/PEPSE.

Answer

Answer: Simon Collins

There are no tests that can diagnose HIV immediately after a possible exposure.

A viral load test (which is not approved for diagnosing HIV) can show whether virus is present in seroconversion – but this is usually at least 1-2 weeks after exposure. HIV antibody tests will pick up most infections after 6-8 weeks, but usually 12 weeks is recommended for the greatest accuracy.

The term for using HIV drugs immediately after exposure is Post Exposure Prophylaxis (PEP). PEP is recommended to be taken within two hours of exposure and a maximum of 72 hours afterwards – the earlier is definitely better.

The reason you may have been given a ‘rapid HIV test’ – where the results are available within 10-30 minutes – before starting PEP, was to confirm that you were not already HIV positive, without having realised it. If this was the case, then you would need to look at HIV drugs in terms of treatment rather than prophylaxis, and a different combination is likely to be used.