[Question #311] Follow Up on Cat Scratch and HIV Risk

35 months ago
Dear Dr. Hunter Handsfield, 

It's Jedd again. I am following up with you one last time in regards to my testing that I had done 22 days post PEP, following my cat scratch incident 2 months ago. If you factor in 3-4 days for the PEP medication to completely leave my body, where testing would be unadulterated, I was tested approximately 18-19 days after finishing PEP. If I recall correctly, you considered this a non risk anyways. 
On my testing, I received a non reactive/negative result on my FDA approved Aptima HIV PCR RNA test, p24 antigen test, and my antibody test. This is all in line with what you expected in your last series of messages to me. 

Can I bury the hatchet on this now? Would you say that I am in the clear so to speak? I know that you typically recommend testing out to 3 months with ***actual*** exposures. Based on what you told me last time, this incident with the kitten would not have even warranted PEP in the first place. All of this has likely added unnecessary stress into my life. Looking forward to your response... Hoping to close a chapter in my life.
35 months ago
****For reference... Here was the initial content I submitted to Dr. Hunter Handsfield in my first of several messages:

My name is Jedd. I had a recent encounter one and a half months ago with an HIV positive friend of mine and a cat. The cat scratched him and did not draw any sort of blood initially. He had to squeeze the paper cut type wound for any blood to appear, which was a minor trace amount anyways. Then 4-5 minutes later, the cat came over and scratched me very lightly in two places on my hand and wrist. The scratches barely turned red from blood. 

My friend's viral load was 20-30 copies per milliliter at the time. He is on ART medicine and has been on it for 3 years. However, on his drug regimen of Truvada and Isentress, he had been off of his Isentress for 3-4 days prior due to prescription refill issues. He was still on the Truvada though at the time of the incident. I don't know if that can cause an undetectable viral load to spike to 50,000 copies or more suddenly or not.

Anyways, I rushed to the ER afterwards in a panic and got on PEP (Truvada and Isentress for 28 days). I got the drugs into my body within 2 hours of the incident. I had a minor cold on the 20th day of PEP. It lasted 2.5 days. My temperature went to 99.5F. I also had a minor stomach pain for 1.5 days on the left side of my body. My temperature went up to 100.2F for 4 hours. The pain immediately went away after this. 

I also want to mention that I have no way of knowing if the cat claw that scratched him also scratched me (cats have many claws)... and also that I checked with a vet practice and they said cat claws are not like hollow point needles. They are actually solid claws and not like snake fangs. 

What are my risks for an exposure like this? Does HIV dies with contact to the air for 4-5 minutes? What impact does my friend's undetectable viral load have on this situation? Why am I still feeling somewhat fatigued and kinda worn down?
Edward W. Hook M.D.
Edward W. Hook M.D.
35 months ago
Welcome back to the Forum.  Today I will be addressing your continuing questions rather than Dr. Handsfield.  Having worked together for decades, while our verbal styles may vary, was ALWAYS agree in our facts and assessments. I have reviewed your prior interaction and agree 100% with his earlier assessment and advice. the exposure you describe was essentially no risk on multiple counts and this is not a situation in which I would suggest PEP.  Having said that, you have now completed PEP, retested more than two weeks following completion of PEP with three very sensitive tests which would have detected infection had you been infected by the cat scratch you describe.  It is now time for you to put your concerns behind you and move forward without concern.  There is no medical need for further testing.  I am sure that some, more conservative persons might suggest additional testing at three months following completion of PEP but again, based on the biology of the infection, current experience in taking care of patients exposed to HIV and extrapolating data from many studies, there is no realistic reason for further concern.  I hope that my comments will help you to move forward from here.  Take care.  EWH
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35 months ago
Dear Dr. Hook, 

Thank you so much for the follow up. I feel like doctors who are not trained in Infectious Disease may be more inclined to take the hyper conservative route with this scenario I have presented. This is understandable, since it is not something they have to encounter on a day to day basis. I really appreciate your feedback and I wish you a very happy upcoming holiday! Thanks again!

35 months ago

Dear Dr. Hook, 


In case you were curious, here is the math behind the incident I encountered:

Here is how it all breaks down with probabilities... Take 23/10,000 (CDC estimate of HIV transmission from a needle stickā€¦ A cat claw would be significantly less I believe).... Multiply that by 2/18 (chance of having the same cat claw poke me in the two spots on my arm and wrist... Cats have 18 claws)... Multiply that by 1/10 (Chances of a transmission after using PEP, which assumes that PEP is 90% effective if taken in a very urgent manner).... Multiply that with 6/100 (Approximate chances of transmission from my friend who was on ART therapy with a very low viral load)... Multiply that by 3/100 (Approximate likelihood of HIV transmission with the drying of HIV fluids according to the CDC)... And finally, multiply that by 1.7/100 (This is the sensitivity of the Aptima HIV PCR RNA test)... You get approximately 1/1,278,772,378. Again... These are all approximations based on CDC information and content found on Mayo Clinic and other sites. Just thought you'd find this interesting.


Edward W. Hook M.D.
Edward W. Hook M.D.
35 months ago
thanks for these calculations.  I do believe they are in the right "ball park" regarding your risk of infection and, if anything, may be a bit low for reasons such as the lower risk of a claw carrying infected blood when compared to a hollow point needle.  Thus, we both agree, it is time for you to move forward without concern.  Take care. EWH
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35 months ago
Dear Dr. Hook, 

One last follow up question... I know that I have tested negative on my tests, which are very accurate. However, I have been off my PEP for a month now and I feel fatigued... I had a bout of gastroenteritis and I am concerned that this may have been brought on by PEP. It has now evolved into something I would describe as most closely resembling post infectious IBS. I have been feeling chronically mildly fatigued, stools seem to be slightly disrupted. I am on omeprazole now, which has helped in solidifying my bowel movements. Still, I feel like my body isn't absorbing the same amount of nutrients before I took PEP. Thoughts?  
Edward W. Hook M.D.
Edward W. Hook M.D.
34 months ago
I am not aware of any data to suggest that poor nutrient absorption is an effect of taking PEP.
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