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.
So I was pretty sure I was exposed to hiv after having sex with a woman that I didn’t know very well and she said she was clean. I have herpes and by the next day I had diarrhea and the day after I had diarrhea, felt hot, muscle aches, a lot of symptoms that sounded like HIV. I got on pep 62 hours after exposure but I’m wondering since I have herpes did the hiv take hold that quick and is PEP not even going to work? I’m taking it and I’m on day 5 but I still feel some of the symptoms. Everything I see online saying it’s impossible for symptoms to start that fast but that’s probably not someone that has herpes. I’m freaking out and just wanna know if I’m wasting my time or will possibly be okay. I understand the risk I took but my anxiety is taking over.
Hi Chris, even with herpes HIV cannot cause symptoms this fast. This is why it is still effective to take PEP up to 72 hours after an exposure – which you did.
Hi Tino, as you started PEP within a suitable time and completed the course it is very unlikely your symptoms are caused by seroconverting.
You can test at 4 weeks post PEP using a 4th generation antigen/antibody test. This result will be 95% accurate. A second test would be required 2 weeks after for a conclusive result.
Hi, I was exposed to HIV on the 3rd of August and I started my PEP course 66 hours after exposure.
I completed my PEP course on the 3rd of September and I went to get tested on the 25th of September(56 days after exposure and 22 days after exposure.) I tested negative using the anti body test kit. My reasoning for testing is that I been experiencing a sore throat,itchiness and body aches. Could I possibly be in my seroconversion period and if so when can I get an accurate test result? 4 weeks after the PEP completion date or later on?
Hi Keenan, please speak with your doctor about possible causes for your symptoms. As you have been testing negative HIV is not the cause. Your doctor will need to investigate for other things that may be the cause of this.
Hi, I’m negative after 89 days after exposure and 79 days after pep. But my knees hurt, got diarrhoea and still have rash on my body. What could be the cause ?
Hi Victor, did you have a question?
Hi
Hi Funky, are you still taking PEP? PEP is a course of treatment that is only for 4 weeks.
It is good that you have already tested negative. Tests are conclusive 6 weeks after the last dose of PEP using a 4th generation test.
Am on my sixth weeks after initial exposure…. still negative and scared… i do the test at home