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HIV exposure and testing


I have an oral sex from Jan 15th 2016. My local doctor prescribed PrEP with "tenofovir disoproxil and emtricitabine". I completed the medication in Feb 11th 2016. 2 weeks later, I took the 4th generation test (combi test) and negative. I am going to take the test after 3 months on this weekend by rapid test as my local doctor's requirements. However, I am so worried and stressed that it turns into positive. Could you please help to advise my likelihood of negative status in this case?
Thanks so much,


Hi there and thanks for reaching out to the AIDS Vancouver Helpline. My name is Colin and I am happy to answer your questions today.

I see you are feeling anxious about waiting to take a conclusive test after having oral sex on January 15th. I hope the information I will provide can be useful to you.

First of all, you mention that the encounter was oral sex. Oral sex as a rule is considered a low risk activity (negligible risk if you were the receiving partner). For there to be a successful transmission of HIV there must first be HIV present. Next there must be an exchange of bodily fluids with direct access to the bloodstream. Additionally, once exposed to the air for even a few seconds, while it doesn't die, HIV is immediately rendered non-transmissible meaning it can no longer be passed on from person to person. Because these conditions are less likely to be met in oral sex, it is considered a low risk activity.

I was a bit confused about your mention of PrEP. Generally if prescribed PrEP, it is not for 2 or 3 weeks but something you would be taking indefinitely to protect you from HIV. There is something called PEP (Post-Exposure Prophylaxis) which is prescribed by a doctor within 72 hours of a high-risk exposure and is taken for 28 days and has proven quite effective at halting transmission of HIV if taken properly. Is it possible that this is what you were referring to instead?

Either way, the 4th Generation Test is the most modern and sensitive commonly-administered HIV test on the market today and most HIV specialists and the WHO consider its results conclusive at 6 weeks post-exposure. Given the timeline you describe, it seems like your first test date might have been a few days short of 6 weeks post-exposure but could be taken as a good indicator of your negative status. Unfortunately taking an appropriate HIV test at the right time is the only way to be sure of your status; but, feeling stress over waiting for the test and its results is normal. Try to focus on the fact that it was a low risk exposure in the first place, and the test you've already taken is a good indicator of your status.

I hope the information I've been able to provide will be able to give you some peace of mind. Please feel free to post again if you'd like any information or clarification.

All the best,


AIDS Vancouver Helpline