| Level I | Good quality evidence |
Systematic review of RCTs with consistent findings High quality individual RCT |
| Level II |
Limited quality patient orientated evidence |
Systematic review of lower quality studies or studies with inconsistent findings Low quality clinical trial Cohort studies Case-control studies |
| Level III | Other |
Consensus guidelines, extrapolations from bench research, usual practice, opinion, disease-oriented evidence (intermediate or physiologic outcomes only), or case series |
[47] Non-occupational PEP: South African HIV Clinician Society. Post-exposure prophylaxis guidelines. The S A Jr of HIV Med, Winter 2008.[Online] Available at:http://www.sahivsoc.org/upload/documents/guidelines_nov_2008.pdf