Using this tool, the risk of contacting HIV for this patient would be:
5/ (1000 x 100 x 100) = 1/ 2,000,000
According to the everyday risk table in the article, this is similar to the risk of dying in the next 12 months from lightning. You left her to decide on PEP.
As the author pointed out, the risks cited are probabilities instead of exact measurements. This is an important caveat.
I find this helpful to provide context, especially for those who have difficulty deciding on PEP.
Vertesi L. Risk Assessment Stratification Protocol (RASP) to help patients decide on the use of postexposure prophylaxis for HIV exposure. CJEM : Canadian journal of emergency medical care. 2003, 5(1), 46-8. PMID: 17659153
Read the free article from CJEM.