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
Following vaginal sex (with condom) with an unknown partner in a high HIV incidence area, I took my first dose of PEP, 7 hours after exposure then vomited 3-4 hours later. I took another straight away. I took the following day’s as scheduled, at the time of the first pill, but vomitted almost immediately. I took another straight away and this one stayed down.
Assuming no other vomitting episodes and following the full course for the next 26 days, is taking additional doses potentially damaging to PEP effectiveness or for any other reason.
Thanks
Hi Thuli, being on your period will not effect your risk. Taking PEP within 48 hours is excellent and will give you the best chance of not getting HIV. PEP is most effective when taken for the full course of 28 days and started within 48 hours after exposure. The effectiveness of PEP isn’t well tested but research shows it is effective in 80-90% of patients when following the course of PEP entirely.
I had an unprotected sex with my HIV positive partner for 2 consecutive days then started pep within 43hours I’m worried ND stressed because I was on last day of my period ND I don’t know how effective can pep be
J, good grief. The doctor sounds right to say you don’t need PEP.
I was taking care of a friend who has HIV but has said his HIV is undetectable however he uses fentanyl so I know he wasn’t taking his medication daily. I was pricked by a needle through his pockets through my pants and on to my skin. I ran to the bathroom and saw that I was not bleeding and could not find a puncture mark. I am on pep but my doctor doesn’t know if it’s necessary as I got it from another doctor. My friend said it was a clean needle but it’s hard for me to trust him. It really felt like the needle did not go through my skin but just prick it very quickly. I washed the site with soap and water. I’m freaking out. Even though I’ve been told it’s very unlikely. The medication is making me so sick I don’t know if I can handle the 28 days I’m sleeping constantly I’m not able to work I’m nauseous. Can anyone tell me if it is very unlikely that I have it and way not have unprotected sex until I get back my results. Thanks
Hi Wathu, how is this person doing? Do they have access to HIV treatment?
I am taking pep after a condom burst with someone who was tested positive after the incident. I started pep 14hrs after the incident and today on day 23 , I am scared , can I take pep beyond 28 days to increase chances of its effectivenes?
Hi Chris,
I think it is important to remember that you are low risk and you took PEP within the window. It’s easy to think of the worst case scenario when you’re anxious and reminding yourself of low risk can help. Different formulations of PEP will all have slightly different side effects but what the symptoms you describe are all quite common. Also, the stress and anxiety will not be helping your side effects from PEP. More information on feelings of fear can be found here: https://i-base.info/guides/testing/hiv-testing-feelings-of-fear-anxiety-and-guilt
Hi
I had partially protected sex with a guy (I was receptive) for about 5-7 mins with no ejaculate. The guy then admitted the day later to being a sex worker (I did know know prior or pay for the sex). I went to my local clinic and they said j was a low risk case but I still started pep just inside the 72 hours, and I mean just by like 20/30 mins. Since then I have had a lot of side effects: nausea dihorea fatigue sleeping issues. I have also had chills with no fever for the last couple of days, could this be a side effect of the pep or could this be triggered by the stress and anxiety of the situation? I do have anxiety anyways (and depression).
When first taking the pep tablet, I took a multivitamin roughly 6 hours after thinking that would be a good idea to help boost my immune system but later my doc told me that could effect the anisotropic of the pep so now I’m worried it didn’t absorb into my system properly.
Just wanting to know if there’s anything else I could do as I’m still paranoid that after pep I’m going to have hiv
Hi John, the risk from most HIV exposures is already very low, and taking PEP will make that even lower. So PEP can be very effective. There are lots of reasons to be optimistic. The HIV test will be accurate roughly 4-6 weeks after the last PEP dose.