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Effect of Daily PrEP on HIV Test?

Sep 17, 2017


I have checked all over and can't seem to find a definitive answer to this question. I take PrEP daily and get tested frequently. My question is does taking PrEP on a daily basis affect 4th generation HIV tests? That is, could PrEP use result in a false negative by suppressing the virus such that antibodies didn't develop or developed more slowly?

I was the receptive partner in anal intercourse for about 10 seconds. The insertive partner did not ejaculate. I took a 4th generation test at 4 weeks after a possible exposure. It was negative, how confident can I be in this result?

Response from Mr. Jacobs

If you can't find it anywhere else, I'm glad you came to me and The Body.Com!

Short answer to your question is "no." PrEP does not suppress or hide the virus in your cells. It protects somebody who does not have HIV by establishing high levels of the protection in their bloodstream, genital tract and rectum before any exposure to HIV. If exposure occurs, the ARVs stop the virus from entering cells and replicating. This prevents HIV from establishing itself and the person remains HIV negative.

Given the fact that you take PrEP consistently and have been getting tested regularly, your chances of acquiring HIV, even if exposed to detectable levels of HIV, are nearly zero ( The fact that he did not ejaculate inside you reduces that nearly zero to absolutely zero.

Now, let's contrast that with what we know about HIV acquisition on PrEP. There are only two instances of someone acquiring HIV on PrEP with verified adherence to the drug. In both cases, they showed up as HIV positive less than a month after HIV acquisition. And both cases involved receptive anal sex with multiple partners with ejaculation. Again, it's unclear why these two individuals acquired HIV under these circumstances, when there have been at least 100,000 other individuals doing the same thing and NOT one other HIV acquisition. But the point is, in the only two cases known, HIV showed up in a standard test right away.

Ultimately, no matter what I say here, your own experience will be your best confirmation. If it helps, you can always request another 4th generation at week eight. But when that one shows "negative" I hope you will be able to apply your personal data to the empirical research and go forward enjoying sexual pleasure confidently.

For more information about PrEP, testing, and pleasure, feel free to visit the international Facebook group at:

PrEP and self-care?
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