Post PEP Testing

Originally Posted: 
Thursday, March 29, 2012


Hello - thanks for such a great site.  Apparently the CDC and the organization that puts together the testing guidelines after Post Exposure Prophylaxis (PEP) recommends the first antibody test to be performed 6 weeks post exposure.  That is only 2 weeks post-PEP.  
Can you give some insight into why this test is even recommended at all given the fact that PEP delays seroconversion?  Im just trying to get my head around their thinking here, and why the results would have any relevance at all.  
Their second recommendation is 12 weeks post exposure and 3 months post exposure.  I understand those two, as that would be 6 weeks after PEP.  Enough time for antibodies to develop.
I was exposed to an HIV+ female with two sessions of unprotected insertive vaginal intercourse.  I was put on PEP medications within 9 hours of exposure and completed the full 28 days.  I tested negative on an OraQuick Saliva test at 5 weeks, 6 weeks, and again at almost 7 weeks (47 days).  
Yet 13 days after completing PEP, I became very ill with intense fatigue, glandular activity, headache, and noticeable nausea.  I'm not sure that 17 days (post PEP) 47 day (post exposure) negative test has any value or meaning whatosever....
What do you think?

Hi there & thank-you for your questions.

Post Exposure Prophylaxis (PEP) has been the standard of care in health care settings for many years now however, non-occupational use of PEP is relatively new. While we do know that acquiring HIV post-PEP is rare, we are not entirely sure yet just how effective of a preventative tool it is. As such, official guidelines concerning the use of PEP and recommendation around testing are lacking in most countries, provinces, states and regions in general.

Because not enough is known for certain about how PEP may or may not affect the body's normal ability to produce antibodies, should the medication fail and infection occurs, testing guidelines around when to test post PEP vary greatly. 

Before PEP is started, consultation with a medical professional should occur & an individual is usually tested at the time to ensure there is no pre-existing HIV infection. Here at the Helpline, we follow what has been recommended by the BC Center for Excellence in HIV/AIDS which is a follow-up test at 3 months post exposure, 3 months post PEP and 6 months post PEP. In all of the cases of high risk exposure & where PEP was administered, the BC Center for Excellence has never seen a case where an individual tested negative 3 months post exposure or post PEP that later tested positive without any additional high risk exposures. So, your test results at 12 weeks post exposure will still be extremely accurate and indicative of your status however based on that fact that you are certain that it was a high risk exposure and because you took PEP, re-testing at the 6 month mark is mostly a precaution. 

In Canada, OraQuick tests are not approved for use & we do actively discourage individuals from ordering these tests online. Although they can be quite accurate, they have a much higher rate of false positives & there is no opportunity for post test councilling, should the results be positive. So, as long as you have received your Oraquick results by a certified medical professional at a reputable clinic or hospital, your results are extremely indicative of your status.

While it may be human nature to attempt to link symptoms with a particular infection or diagnosis, it is important not to do this with HIV infection. This is because not all individuals experience symptoms at all. If they do, it is generally 2-6 weeks post exposure and after that, there should be no recurring symptoms or chronic conditions. The symptoms you are experiencing may be the side effect of PEP: it is the same treatment as people living with HIV and HAART can be very harsh on the body, especially on the liver and kidneys. Please partner with a medical professional you trust to try to accurately discover the true cause of these symptoms. 

I hope this helps & if you have any other questions regarding HIV and/or PEP, please feel free to call, email or re-post online. I have also included some links/further reading you may be interested in below.

In health,

AIDS Vancouver Helpline
604-696-4666, Monday-Friday 9am-4pm


Submitted by Ronny (not verified) on

Hello, i slept with a female (HIV status unknown) and the condom burst. Consulted a doctor who took a blood test that came back negative. I went on PEP and finished the treatment; now need to know when (after which post PEP/exposure test) is it safe to sleep with my wife without a condom as per usual.

Submitted by monicaf on

Hi there & thank-you for your question.

I apologize for the delay in responding to your question. Due to some Holiday closures and a volunteer shortage, we are a little bit behind. If you would like a more immediate answer to any questions you may have, please call us Monday-Friday 9am-4pm.

Generally speaking, once you have completed PEP, the window period for testing starts. Testing is encouraged at 6, 12 and 24 weeks post PEP.

It is recommended that you test at 24 weeks (6 months) post PEP for completely conclusive results however, there are no documented cases of results changing between 12 and 24 weeks. If you recieve a negative at 12 weeks post PEP, you can be confident that the result is not likely to change.

In terms of deciding when you want to resume having unprotected sex with you wife, that is a private decision that can be made by you and your wife, depending on what you both feel comfortable with.

All the best,
AIDS Vancouver Helpline

Submitted by Ronald (not verified) on

Hi, i had exposed sexual intercause with an infected partner and i was administered PEP TDF/3TC and EFV for 14 days after 11 hours of exposure. then when i went back for the remaining dosage i was given 1 pill/day tablet (m152). i was remaining with 3 tabs in the first case for each (TDF/3TC-m122 and EFV-yellow). the nurse i found withdrew the 3 yellow tabs most likely EFV claiming that i was taking overdose and yet there is a variation between M122 and M152-yellow tab in terms of size. secondly the side effects of M122-white first one is not the same when taken without EFV-yellow as M152 tab. actually M152 1 pill/day tablet had the same side effect like (TDF/3TC-m122 and EFV-yellow).when i took the first tab minus the withdrawn one and realized the difference in terms of side effects i kept the remaining 2 to end with and began on the new i pill tab. i have been very punctual in taking my medicine either early by 7 mins or late by 7 mins NOT beyond this limits strictly till i finished. Kindly advise me do you think there was interruption in the course of action of the drugs in its working? because i have a feeling that the nurse shouldn't have withdrawn the EFV - Yellow tabs since the m122 did not look like 1 pill in its effects as the later pill administered.

Helpline1's picture
Submitted by Helpline1 on

Hi Ronald, 

What it sounds like you are telling me, is that you were started on PEP for the first 14 day that consisted of 3 pills containing TDF(tenofovir), 3TC(lamivudine), and EFV(efavirenz). Later, when you went back to refill your prescription, you were given 1 pill to take daily (going from 3 pills/day to 1 pill/day). You are concerned about whether being on 1 pill/day now means that you are recieving insufficient medication for PEP. In addition, you have decided to keep taking the TDF and EFV that you have remaining in addition to the 1 pill/day you were given. Please let me know if any of what I am understanding is wrong. 

It sounds like you were switched to a combination pill when you went back to recieve your prescription refill. In some pills, multiple HIV medications can be combined in a single pill. This means that instead of taking 3 separate pills for 3 different medications, a single pill can be taken which contains 3 medications. One pill that is often used for PEP is called 'Atripla', and contains FTC(emtricitabine), TDF(tenofovir), and EFV(efavirenz). It is a pink oval pill embossed with the number '123'. This helps to reduce the number of pills a person is taking which may improve the ability of that person to complete their prescription.

What may help is if you speak with your prescribing doctor or the pharmacist you pick up the medications from. Alternatively, you could post back with your complete prescription written out. This would mean the writing on the bottles that you have been given. For example: 'Tenofovir 300mg by mouth once daily for 14 days'. This would help us to identify exacty what medications you are on.

All the best, 

AIDS Vancouver Helpline Volunteer

Submitted by zinzi (not verified) on

Had unprotected sex on monday night was put on PEP on wensday during the day(that wensday I tested negetive)today is the 6th day for me on PEP so I went and do the HIV test it came positive.Is the test correct or how long should I wait to take anather test

Submitted by davidn on

Hello and thanks for choosing the Helpline. All people who test positive for HIV will have a confirmatory test to ensure that this test is indeed conclusive. 6 days after exposure does seem a bit early and you may consider the fact that you had already been living with HIV.

It is now important to keep working with the specialist who prescribed you medication to determine the next best steps going forward in regards to your care and treatment.

Living with HIV is now easier and for most people considered an manageable illness.

Please let us know if we can be of any support for you moving forward.

Yours sincerely,


Submitted by mike (not verified) on

I had a single unprotected sex with a woman and it 3weeks after that I came to know of her status. Can I take PEP? I took a HIV test and its negative, please when do I take the test again?

Submitted by davidn on

Hello as you may have read from this forum post thread, PEP must be taken no later than 2 or 3 days, after a high risk exposure. Taking PEP three weeks after unprotected intercourse will not work.

The HIV negative test you had would be considered conclusive at 12 weeks after your sexual encounter however most people exposed to HIV will develop detectable HIV antibodies at 4-6 weeks, post risk exposure,

If you test was any time before 12 weeks or 84 days, please consider having a final and conclusive test at the 12 week mark.

It must be noted, that having intercourse with an HIV positive person does not mean that they have passed the virus to you.

All the best and good luck with your final tests.


The AIDS Vancouver Helpline is a volunteer-driven information, referral and support service related to HIV and sexual health. Volunteers are trained in active listening, HIV and sexual health information, and local resources and services. Volunteers are not doctors, nurses, or other licensed professionals. Volunteers do not give advice, and strive to provide service-users with adequate information and appropriate referrals.

Helpline volunteers uphold the agency’s confidentiality and privacy policies. Your calls, forum posts, and emails are anonymous. We welcome you to use a pseudonym or “fake name” when using Helpline services.  We will not ask for or track your personal information. To ensure that the Helpline program is providing quality services, the Helpline Coordinator regularly monitors online content (forum posts and emails) and supervises volunteers who are receiving calls.  

The Helpline Program should not be used in replacement of medical examination, diagnosis, advice counseling or follow-up care. We strongly recommend routine testing (HIV and STI tests) and discussing your healthcare directly with a physician.

We would love to hear from you! If you have feedback or questions related to the operations of the Helpline, please contact David at or by calling 604.696.4666.

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