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
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.
Note: This answer was last updated in July 2021 from an original post from December 2011.
hi
I tested after PEP Course 3 months with th hiv combo test. But during the PEP Course My girlfriend and I slept together without protection( she also took PEP the same me). is the result accurate ?
Thanks for your answer
And sorry for my english
Hi Mr. Worry,
After a course of PEP you need to wait 28 days before testing for HIV. This is because PEP can delay infection. So 95 days sounds fine.
Please see this link for more details.
hi,
I would ask you some question.
My girlfriend and I slept together without protection but we both were on pep.
And by the way on day 95 after PEP i tested the result was negative( HIV combo test)
is it conclusive?
Thanks for your answer
Hi Erastus,
What type of test did your girlfriend have? Please see here for the Q&A about different types of tests for HIV.
Was the positive result for an antibody only HIV test? This does not mean that you are HIV positive. It means you need a second confirmatory test. So it is possible that it was a false positive.
Mine is a concern about my fiancee who is internship in kids session.it happen that the kid and mother were both positive and needle pricked my fiance and am worried she tested while on pep and the results came out positive.Am very stressed since we didn’t even have a kid of our own.kindly advice me if this could be false positive
Hi Ric,
I hope you don’t mind but I’ve shortenend your comment. As Angelina points out, the risk of HIV from one broken condom is very low – probably only 1 in 500 if your partner was actually HIV positive and not on treatment.
If your partner had an undetectable viral load on treatment, then the risk will be zero.
I wish to add my opinion and findings, PEP or PrEP if taken with accuracy diligently is very effective.
Hi Jt,
The BASHH guideline sounds straightforward. However, PEP can delay HIV infection. And it’s also important to start taking PEP as soon as possible after exposure to help make it effective.
So there are factors that might make saying that a paticular time or date is absolutely conclusive.
There are many people on this site who say a test at 90 days after the last dose of pep is conclusive. But the latest BASHH guideline say a test 8-12 weeks post exposure with a 4th generation test is conclusive. Can someone please clear this up for me. When is testing conclusive when taking pep? 12 weeks after exposure or 12 weeks after last dose of pep?
https://www.bashhguidelines.org/media/1027/pepse-2015.pdf
https://www.cdc.gov/hiv/pdf/programresources/cdc-hiv-npep-guidelines.pdf
Hi Tj,
Testing after a course of PEP can be done 4 weeks late, so 8 weeks after a possible exposure. If you’ve tested negative at 12 weeks this means that you don’t have HIV.