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 Unknown, as this was protected sex there is no risk of transmission. A french kiss, even with an ulcer is no risk of transmission.
Please see here for more information: https://i-base.info/qa/factsheets/hiv-transmission-and-testing
Hi, i hope you are doing well. Almost 25 days ago i had protected sex with a sex worker, however i had one mouth ucleres in lower lip, and we did french kiss. So i was really worried and i went to hospital and although the doctor told me it is really low risk, i asked him to prescribe PEP, after two weeks i had sore throat and really mild fever but i think i got it from my friends because we got sick in order with almost same symptompes, now on the day 25th, i have some really mild muscle pain and tiredness, a tightness in thorat without pain and no fever (i checked with cameras in my university), also i have some pimples on my chesr, maybe 4 5, is it a sign of HIv? I am really worried, really stressed, i dont eat enough, sometimes i want to end my life, i dont know, i would be grateful if you could help me. Thank in advance
Hi David, unfortunately PEP should be started within 72 hours after an exposure. After 2 weeks PEP will have no effect.
PEP: https://i-base.info/qa/factsheets/pep-faq
I started pep 2 weeks after exposure will pep function effectively
Hi Jacob, you can test to confirm your status 6 weeks after the last dose of PEP using a 4th generation test.
Please see here for more information: https://i-base.info/qa/factsheets/hiv-transmission-and-testing
Hello Sir,
I had sex with a male nurse.. We had anal sex and condom breaks in between. I came to know the breakage after ejaculation. He is claiming to be HiV negative and shown his results taken 2 months back. But still I had the fear of HIV, so I started PEP after 36hours. Today is the last day of PEP. When should I test it again. I have tested all STD before starting PEP. Results are negative. Do i have the chance of getting HIV
Hi Khant, sorry for the confusion. This will depend on the type of test you are using. You can consider the first day of exposure to be the day you take your last dose of PEP.
Using a 3rd generation you will need to wait 12 weeks/84 days after PEP.
Using a 4th generation test you can confirm your result earlier at 6 weeks/42 days after PEP.
Hello. So, I have been reading lots of info on this super useful website. Most of the infos are super clear. But, one info is really confusing.
Let’s say I test with 4th generation test on day 60 after exposure (32 days after completion of PEP) and have a negative test. Do I get a conclusive result if I test again on day 70th after exposure (42 days after completion of PEP) or on day 90th after exposure (62 days after completion of PEP) or on day 118th after exposure (90 days after completion of PEP)?
Hi Andrew, guidelines recommend that PEP is started within 72 hours (some countries suggest 48 hours). Starting within 24 hours is very quick and means PEP will be effective.
Please see here: https://i-base.info/qa/factsheets/pep-faq
Hello. I received oral sex from a sex worker and then introduced my penis into her vagina for about 15 seconds without condom as she asked me to finish inside. She then told me she was positive and not on treatment. I blame myself all the time and I am truly determined to stop having non-monogamous sex, but I am afraid it may be too late.
I started PEP 24 hours after the exposure and I was examined, I took a test and I was explored (negative on all STDs, no open wounds/abrassion, etc). I have been looking at statistics and even though I am aware that it only takes one exposure to get infected and that chances are actually low, there are biological aspects that can increase those risks, and now I am worried.
I am uncircumcised, and her viral load is likely very high as she is not in treatment, and likely hasn’t been for many years (she is 57 years old).
Now I am on my 5th day of my PEP treatment, but thinking that it all depends on it successully functioning kills me as I was told by doctors that likelihood of working steadily drops after 6 hours post-exposure.
Please help