Xhost - here's a quick summary from a recent post I had regarding PEP. In addition to these, there are some studies from 9+ years ago that indicate delayed seroconversion although the studies don't mention PEP or HCV coinfection.
There's been some interest and debate here on the effects on PEP on seroconversion in patients who seroconvert, so I did some research. Here's what I've found:
The general consensus is that PEP does not, except in rare circumstances, impact the time to seroconversion.
A case of delayed seroconversion in a treated monkey suggests that delayed seroconversion may occur in the context of human PEP, although this has not been reported in either the occupational or non-occupational setting except during co-transmission with hepatitis C [4, 11, 29].
Three instances of delayed HIV seroconversion occurring in HCWs have been reported; in these instances, the HCWs tested negative for HIV antibodies >6 months postexposure but were seropositive within 12 months after the exposure. Two of the delayed seroconversions were associated with simultaneous exposure to hepatitis C virus (HCV).
There are currently 6 worldwide case reports of HIV seroconversion despite combination HIV PEP. (2003 study)
[Effectiveness of nPEP]
Since there has not been a CONCLUSIVE study of the effect on PEP of timing to seroconversion, current recommendations are still to test through 6 months. For practical reasons, it is unlikely that any detailed study of timing to seroconversion (with or without PEP) is forthcoming.
1. Prescribing PEP after low risk exposures needs to be considered very carefully due to the risk of liver toxicity, which is potentially more life threatening than HIV. For certain 'borderline' situations, like mine, I think that the decision needs to be made in collaboration between the doctor and patient.
For example, prescribing PEP for oral exposure (low risk) to a person of unknown serostatus (? risk) would be unwarranted.
Prescribing PEP for anal exposure (high risk) to a person of unknown serostatus (? risk) would be recommended.
But prescribing PEP for oral exposure (low risk) to someone of KNOWN HIV+ serostatus (high risk) is a 'borderline' case that I think warrants discussion.
Due to the unknown effects of PEP on seroconversion, I think testing through 6 months is good practice, regardless of exposure type, although 3-month tests are probably VERY reliable.
If I had to do it all over again, I'd definitely go on PEP. I'd never want to wonder 'what if' if I were ultimately infected after having decided against PEP. But PEP was definitely no picnic, so I wouldn't look forward to it!