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.
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.
Hi Martha, as you started PEP within 72 hours of exposure it will be effective.
Hi , my name is Martha,I had unprotected vaginal sex with a guy whom I later tested and the results were positive. I rushed to a hospital and commenced pep on the 30th hour .I am so worried Will pep work for me?
Hi Green, if you use a 4th generation antigen/antibody test you can test after 6 weeks from your last dose of PEP. If you use a 3rd generation test (only antibody) you will need to wait 3 months from your last dose of PEP.
If you use 4th generation test and test negative at 6 weeks you will not need a follow-up test at 3 months. Your result would be conclusive.
Hi, after finishing PEP, I tested negative at 3 weeks. I read that since I tested before the 6 weeks I need to test again at 3 months? What if I test negative at 6 weeks, will I still need that 3 month test?
Hi Timothy, as your partner is on medication it is likely that she cannot pass on HIV. This is explained by U=U: https://i-base.info/guides/testing/uu-undetectable-untransmittable
This means there is a very low risk of transmission. In the UK this would not be an indication for starting PEP. Taking antibiotics will not reduce the likelihood of HIV transmission. Antibiotics are used for bacterial infection and HIV is viral.
Good morning all. I have sex with hiv patient who is on drugs since 2019. She took the drugs before we had sex. After sex I took antibiotics drugs. What are the chances of getting hiv. Am scared.
Hi Ndemon, as your parter was on treatment with a stable viral load it is likely that she could not pass on HIV. In the UK this would not be considered a risky exposure and PEP would not be indicated. The symptoms of flu are very general. It is much more likely the flu rather than HIV. Your history does not suggest you are at risk of HIV: unlikely your partner could pass it on, started PEP immediately and you finished the course of PEP.
Please follow this link for more information about testing and transmission: https://i-base.info/qa/factsheets/hiv-transmission-and-testing
Hellow dear Josh I had sex with the girl who is HIV postive but she is on treatment and virus is stable, within 3 hours I was taking Pep and I completed 28 days.now i exprience flue i worrid this is indicator that iam postive already
Hi Rabbit, your doctor is correct. It is too soon for your symptoms to be related to seroconversion. While you are on PEP, HIV is suppressed and so seroconversion is delayed. These symptoms present 2-3 weeks after exposure if at all. In your case this would be 2-3 weeks after finishing PEP.
You have a very low risk of HIV transmission. Oral sex carries little to no risk of transmission. Saliva contains antiviral properties which makes HIV transmission very difficult in this route. Kissing and grinding will have no risk of transmission. As you are now on PEP, your risk is even further reduced. In the UK this would not be considered an exposure that would require PEP.
Testing cannot be done the day you finish PEP. As PEP suppresses HIV, results would not be accurate straight away. For a 4th generation antigen/antibody test you can test from 6 weeks for a conclusive result (the result is 95% accurate from 4 weeks). An antibody test (3rd generation) will be conclusive from 3 months.
Please follow this link for more information about testing and transmission: https://i-base.info/qa/factsheets/hiv-transmission-and-testing
I had oral sex with a guy where he rimmed me, I gave him a bj and we kissed a lot. I grinded on him until I ejaculated on his hip. He did not ejaculate. He kept trying to put his dick by my ass whilst we were kissing which I am glad I kept moving away.
I went on PEP 5 to 6 hours later and managed to convince him to get a test me a week later and he tested positive. I am on PEP I have been taking it at the same time everyday more or less (15 minutes give or take) only on day 9 did I take it twice and 8:50am and 04:16pm. On day 10 I proceeded to take it at 10.
I am concerned because day 7 I went back to the doctor and told her I feel like I am catching a flu. She checked me out and gave me some antihistamine and advised that it’s to soon for seroconversion. Day 10 I went back and she advised that it’s still to soon and I should continue on the meds accordingly.
1.What are the chances of my contracting hiv?
2. How accurate is the result on the day after I finish PEP
3. Are these flu symptoms a sign of HIV. The pills I am on are acriptega