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 Zj, PEP is no longer effective in the body after 24 hours from your last dose.
PEP can remain in the body longer than this and cause some side effects (if you were experiencing them while you were taking them daily). In these cases PEP will completely be removed from the body within a couple of weeks from the last dose of PEP.
hi how long does pep stay in the body after finishing the course
Hi Jean, HIV symptoms do not present so quickly after an exposure. Your current signs that you are experiencing are not caused by HIV.
PEP is effective when started within 72 hours. As you are starting at 60, even with the signs you have there is no reason to think it will not work.
PEP: https://i-base.info/qa/factsheets/pep-faq
hi i took pep i think about 60hours of exposure when i hard already started getting some signs i asking if it had happened before and worked
Hi James, as you have been on PEP it means you are unsure of your status. For this reason it is not recommended to have sex without a condom until your status can be confirmed.
After PEP, the earliest you can test is 6 weeks after the last dose using a 4th generation test. From this point onwards it will be confirmed if there is any risk to your wife or not.
I had unprotected sex on the 22 November Wednesday around 20pm and i was given pep TLD Friday around 09:30am. Today 18 December am remaining with 3 days to finish the course. So when can I start having sex with my wife?
Hi Reza, you are are right. Both of these exposures will be covered by your course of PEP.
thank you for your reply josh so the 7am and 9am exposure on the same day covered?
Hi Reza, no this will not affect the effectiveness of PEP. As you started PEP within 72 hours of the earliest exposure it will still be effective.
PEP: https://i-base.info/qa/factsheets/pep-faq
Hey josh is pep still applicable with this scenario i had sex with a person has hiv at 7am and we did it again at 9am on the same day(august 31)and i took pep at 11pm in september 1. So basically my first sex exposure at 7am(is 40hours after exposure) and at 9am(38hours after exposure)with the same person.since its still covered at 48hours window period.does it affect the effectiveness of pep?