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 Khatiwada,
We don’t have data to say how many people don’t become infected with HIV if they take PEP. However, as the above post explains the risks are dramatically reduced if someone takes it within 48hrs.
Side effects vary, and are discussed here:
http://i-base.info/qa/853
How many percentage of this clinical trial patient are seen negative after PEP is completed?
What are its side effect?
Hi Zee,
The above link discusses PEP.
Info about Trivenz, (a generic version of Atripla) can be found here:
http://i-base.info/guides/1561
However, its important for you to know that because the guy you had sex with has an undetectable viral load, the risk of transmission is close to zero. For more info, please see here:
http://i-base.info/qa-on-the-partner-study/
Hi. Today at about 16:00pm I had anal sex with someone who has HIV , the condom broke and he told me that he has the HIV. I was very upset. Long story short. He told me that his HIV status is “undetectable” , I have no clue what that means. I rushed to the doctor and told her about what happened. I was immediately tested to see my current HIV status, which was negative. The doctor gave me Trivenz tablets that I should take for 30 days, and then I have to return 2 weeks after I finished these tablets and get tested again.
I have been so worried for the last few hours, as this is something new to me.
All I want to know is , how accurate will the HIV result be after these 6 weeks.
Will alcohol, food and cigarettes have an effect on this treatment?
Are there any Do and Don’t while using this treatment?
Hi A,
For PEP to most effective it should be taken as prescribed.
Hi. Thank you for the article. Can the PEP course be safely reduced to some extent and still be effective? Any evidence of this? I have jaundice and rash (ATAZOR is one of the medications), and it is just a tenth day (professional hazzard). So was just wondering. Thank you.
Hi David,
Once you’d finished the course of PEP you should have tested. Did you do this? If not please see Q1 here:
http://i-base.info/qa/what-are-the-most-asked-questions
I had sex with a lady that said she was HIV positive. I took the PEP after exactly 32 hours for 30 days. After a few days I noticed I left just 1 pill out of the 3 types I was given by the doctor. I slept with her once and only once and it lasted for about 20 minutes. It was December 2016 and I started having symptoms in March. I had a boil on my behind and now its May I have a headache and a sore throat. What are my chances of contracting the disease as I would like to test in June?
Hi Hannah,
Please see the above post, and Q1 here:
http://i-base.info/qa/what-are-the-most-asked-questions
I had a needle prick from checking a kid’s RDT status. By then I didn’t know the childs status I got to know the child’s status within the last 72hours of exposure and I started taking the PEP. Am I likely to get the infection?