Question

Is PEP effective if taken 48 hours after exposure?

I paid for sex with a woman but the condom tore and I only realised after I was done. There is a high chance that she was HIV positive. I started PEP after 48 hours.

I got a PCR test done 17 days after exposure. It had a less than 20/ml (undetectable) result.

Now between 14 and 35 days after exposure I have had signs of thrush, mild red rash on my face and a couple elsewhere. But no fever or swollen lymph glands.

Can the rash and thrush be because of utter stress and obsession?

My doctor says that the PCR can be relied upon and that I am negative.

Can the PEP have reduced the viral load to less than 20/ml as I took it for 15 days before the PCR test?

Please give your expert advice. I am very anxious. Thank you.

Answer

Thank you for your question.

The risk of HIV from one broken condom is very low. If your partner had an undetectable viral load on treatment, then the risk would be zero. If they were not on treatment the risk might still be only 1 in 300 or lower.

You cannot guess someones HIV status so your assumptions might also be wrong.

You started PEP within 48 hours, so it is likely it will work.

PEP – stands for Post-Exposure Prophylaxis. It is a term used for taking HIV drugs to reduce the risk of infection. PEP usually involves taking a combination of three HIV drugs for one month. The earlier PEP is started, the more likely it will work. Ideally, this should be within a couple of hours. If this is not possible, then still the earlier the better.

Some guidelines include a two-day window to do this (i.e. within 48 hours). After this, effectiveness is much less likely. Other guidelines allow up to 3 days (i.e. within 72 hours). Sometimes this may be more for psychological benefit. For example, if someone is very stressed or traumatised.

No guidelines recommend starting PEP after 72 hours.

After finishing PEP you need to wait a 4-6 weeks before testing.

If the PEP has worked, or the person was not initially infected, this will show as a negative HIV test. The test you did 17 days after the exposure will not be accurate yet.

If the PEP has not worked, this will be shown in a positive test result. Testing 4 weeks after PEP will detect 95% of infections. Testing after six weeks will detect more than 99% of infections. This result doesn’t need to be tested again.

If PEP has not worked, serosonversion usually occurs 1-3 weeks after PEP is finished. However, only 80% of people show symptoms.

Please test 6 weeks after you finished PEP is finished. If you test any earlier, you need to take a second test 3 months later.

Viral load (PRC) tests are not approved to test for HIV. In some cases they can have a role.

Please see a doctor to talk about your symptoms he best way to confirm what is causing them is to see your doctor. He/she will be able to diagnose and treat the symptoms accordingly.

Please see this link for more information about PEP:
https://i-base.info/qa/factsheets/pep-faq

Note: This answer was last updated in July 2021 from an original post from December 2011.

846 comments

  1. Lisa Thorley

    Hi Ryan,

    Its great to hear that you’ve tested negative, to be safe you should have another test after a month of possible exposure. Its very unlikely that the PEP will be doing anything for you as it was taken late.

  2. Lisa Thorley

    Hi Sadguy,

    Even if the woman that you were with is living with HIV, you can’t contract HIV in the way that you’ve described. Therefore, you don’t need PEP.

  3. SadGuy

    Hi Lisa,
    I’m curious if I should take PEP as I touched /licked a girl’s clit for 2-3 seconds. I had tongue inflammation/ ulcer but no bleeding that night. We had deep throat kissing but no love-making. I don’t know her status too. Please help! I’ve 24 hrs to decide on PEP.

    ~SadGuy

  4. Lisa Thorley

    Hi Ryan,

    PEP needs to be taken within ideally 48hrs, and definitely within 72hrs. Therefore, if there has been a risk the PEP is unlikely to do anything. You’re going to need to test.

  5. Ryan

    Hi
    I had sex with guy at 2am without condom I don’t know his hiv status i found him on the app but I saw his profile was negative I think he was positive but I am not sure! and I went to cityMD and I tell my story to the doctor and He gave me Truvada and Tivicay I didn’t get it in 72 hours I got it in 85 hours I am just worrying that was my first time before getting the drugs I tested I was negative than I got the drugs and I promise I will not gonna do this again I am boy and I just worrying I will be negative or not please Answer in question I will be fine or not?

  6. Lisa Thorley

    Hi Thabo,

    Ideally PEP should be taken within the 48hrs as the above post explains. However, even it may work even if taken up to 72hrs after a possible exposure.

  7. Thabo

    Please assist me, I need to take my PEP TREATMENT, but now I’m drunk, and my 72 hours is today, can I take it?

  8. Lisa Thorley

    Hi Victor,

    Its not possible for us to say if you’ll be positive or not, this is why you need to test once you’ve finished your course of PEP.

  9. Victor

    Am Hiv Negative and i start take PEP within 67 hours, so can i be able to escape to hiv?

  10. Lisa Thorley

    Hi Fred,

    The ARVs that someone is offered for PEP varies from country to country. Where is it that you live?