Question

Is PEP effective if taken 48 hours after exposure?

2 July 2021. Related: All topics, PEP/PEPSE.

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

Answer: Angelina Namiba

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. Suraj •

    Hi
    After 30 days to finish my pep medicine my hiv test result is negative . But now these I have very stress about my hiv position .
    Can u suggest what can I do.

  2. Roy Trevelion •

    Hi Suraj,

    Please see question 1 here:
    http://i-base.info/qa/what-are-the-most-asked-questions

    And the guide to PEP here:
    http://i-base.info/pep-and-prep/

  3. Suraj •

    Hi
    After 30 days to finish pep my result is negative it is Conclusive or further tested.
    Can I repate test or not.

  4. Roy Trevelion •

    Hi Rahul,

    The number has a qualitative value, so it’s more accurate and not just a yes or no answer.

    Please see this link for your second question.

  5. Rahul •

    Hi i am rahul
    Thanks for reply ing my answer .
    But my question is if the index value is only a number why it change. In my three tested i.e 0.07,
    0.13, 0.16 .

    Also my second question after 34 days to finish my pep medicine my hiv test is negative how accurate it is

  6. Roy Trevelion •

    Hi Rahul,

    The number is a more accurate (quantitative) way of measuring the result other than a simple, yes or no. If the number is less than 1.0 the result is negative,

    If the result is above 1.0 the result is positive. Please see this Q&A.

  7. Rahul •

    Hlo sir, my name is rahul. I had unprotected sex with man. After my sex I take pep medicine with in 48 hours. My pep medicine is completed on 26 June 2019 than I go for hiv screen test .
    First on 3 july 2019 and the test result is nonreactive and index value is 0.07 after that
    On th 17 july 2019 I go for another test and the test result is nonreactive and index value is 0.13
    After that I go for another test on 2 Aug 2019 and the test result is nonreactive and index value is 0.16
    These test are done in same lab. I know that nonreactive mean is negative. But my question is why my index value is increasing ?
    What indicated index value?

    My question is what about my hiv status.

  8. Roy Trevelion •

    Hi Rohit,

    We do not have the resources to answer questions about risks of transmission and testing. But please see this link to to all FAQs for HIV testing.

  9. Rohit •

    Hi I am rohit
    I had unprotected sex with man 15 months( april 2018) ago after eight month (march 2019) of sex exposer I go for hiv combo test and my test result is negative .
    One month ago i had unprotected oral sex with the same person in June 2019 .
    After the my sex exposer I go for hiv test (15 days) and my test results is negative.
    What is my hiv status?
    And when i go for another test.

  10. Roy Trevelion •

    Hi Rahul,

    Non reactive means HIV negative. But you need to wait for 28 days after finishing PEP to take an HIV test. That’s because PEP can delay infection.

    Please see this link to more info about PEP.