[Question #1095] hiv acquisition through herpes blister under pants?

50 months ago
Hello to Dr Handsfield and Dr Hook,

Yesterday I was at the sexual health clinic and didn't think much of it until I got home and realised that I had what is likely a herpes blister on my buttocks right on the spot I sat on the chair. If you had an active herpes lesion and then sat on infected blood, does this pose a risk of aquiring hiv? I did have pants covering the blister, but am concerned any blood would've soaked through the pants.  

I am very concerned as I know the presence of these blisters can greatly increase the chance of acquiring hiv. 

Thank you for your time
Edward W. Hook M.D.
Edward W. Hook M.D.
50 months ago

Welcome to the Forum and thanks for your question.  You are correct, that contact with infected secretions during sex when an ulcerative STI such as herpes of syphilis is present is associated with about a three-fold increase in risk of infection.  The good news however is that the situation you describe was a no risk event.  There are several reasons I say this with complete confidence.  First, STIs, including HIV are not passed through clothing, even if that clothing were to get wet with genital secretions.  The second reason this was a no risk event is because the HIV virus, like other microbes causing STIs is quite fragile and becomes non-infectious on exposure to air.  Finally, from a statististical perspective, the chances that the person who sat in the chair before you had HIV and then left infected blood behind that you did not see when you sat down is incredibly low as well.  For any of these three reasons there is no realistic chance that you could have acquired HIV in this way and when you consider all three reasons, there is absolutely no risk to the situation you describe.  No reason for concern, no reason for testing.

I hope that this information is helpful to you.  EWH

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49 months ago
Hi Dr Hook, thank you for your reply addressing that issue. I was wondering if you wouldn't mind answering another question as part of my two follow up replies. I have a concern about when I was in a recent medical facility. Before taking my blood, the phlebotomist used a pen to write something then immediately felt for my vein with the same hand and slid the needle in. If there was anything on that pen (like blood), she's transferred it directly to the site where she slid the needle in. I know this a bizarre scenario and probably difficult to estimate the likelihood of infection..but do you believe I should be retested in a few months? My arm bruised horrendously afterwards which has never happened before, adding to my concerns. 

Thank you for your time
Edward W. Hook M.D.
Edward W. Hook M.D.
49 months ago
It seems that you are quite worried about becoming infected with HIV through transmission at the time or place of medical care.  I cannot tell you how frequently such transmissions occur because they virtually never occur and there are no scientific studies of the topic.  Your phlebotomist did not follow recommended procedure and should not have touched the pen before drawing your blood.  Despite that, in my estimation, your risk for infection is immeasurably low and if I were you, I would not worry or feel the need for further testing.  The chance that infectious material was transferred on a finger from the pen is virtually zero.

I hope this comment is helpful to you. EWH
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