[Question #6645] Window period of NEW sex after HIV PEP medication (question for Dr. Handsfield)

12 months ago
Dear Dr.  Handsfield, 

Greetings! 
I am very worried about how HIV PEP would affect my antibody responses and window period. 

Here is my case:  
15 months ago after one sexual exposure, I took HIV PEP (Isentress and Combivir or Isentress and Tenofovir. Sorry, I forget the exact medications).  
I completed the whole 28 day PEP course and got tested negative on Combo test at six and twelve months after the exposure.

15 months after the sex, I had a new sexual exposure. (There were no any other exposure between the two.)  

Here are my questions:

(1) I am wondering whether the 28-day PEP medication taken 15 months ago would possibly still stay in my system and be able to        
     oppress HIV virus to any extent, if I was infected in the new exposure

(2) How long can the 28-day PEP medication taken 15 months ago stay in my system and affect/delay my antibody responses?

(3) Would the 28-day PEP medication taken 15 months ago affect or prolong the window period of NEW and AFTERWARD sex exposure, if any?  

(4) Given the 28-day PEP medication taken 15 months ago and its possible effects, when can I have conclusive test result for the new 
      exposure? 

Dear Dr.  Handsfield, please kindly address my questions. Thank you very much !
Edward W. Hook M.D.
Edward W. Hook M.D.
12 months ago

Welcome to the Forum.  Dr. Handsfield and I share the forum and by chance I will be answering your question.  We have worked together for nearly 40 years and the content of our replies are always the same despite the differences in our verbal style.

You don't provide much detail about the nature of your exposure but most single exposures are relatively low risk for HIV.  In all instances, even in the unlikely circumstance that your partner had HIV there is a greater than 99% chance that you were not infected.  With that as background I'll answer your specific questions:

(1) I am wondering whether the 28-day PEP medication taken 15 months ago would possibly still stay in my system and be able to oppress HIV virus to any extent, if I was infected in the new exposure
Your PEP taken over a year ago would NOT offer any protection from your recent exposure.  The medications taken for PEP stay in the body less than a day.  That is the reason that PEP must be taken every day.  There would be no residual effect of PEP even 2 or more days after your last dose of medication.

(2) How long can the 28-day PEP medication taken 15 months ago stay in my system and affect/delay my antibody responses?
Please see my comment above.  The medications taken for PEP stay in the body less than a day.

(3) Would the 28-day PEP medication taken 15 months ago affect or prolong the window period of NEW and AFTERWARD sex exposure, if any?  
No.

(4) Given the 28-day PEP medication taken 15 months ago and its possible effects, when can I have conclusive test result for the new 
      exposure? 
Test results following an exposure to a potentially infected partner using combination HIV antigen/antibody tests are more than 99% conclusive 4 weeks after an exposure and completely reliable at 6 weeks (42 days) following exposure.

I hope this information is helpful.  EWH 
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12 months ago
Dear Dr. Hook, 

Thank you for your reply.


(1).Given your reply:
    Your PEP taken over a year ago would NOT offer any protection from your recent exposure.  The medications taken for PEP stay in the body less than a day.   That is 
    the reason that PEP must be taken every day.  There would be no residual effect of PEP even 2 or more days after your last dose of medication.

      Since English is a foreign language to me, I don't quite understand what you mean by "2 or more days." What does "or more" mean?  Does it mean "more or  less"          
      or many more days or weeks? Sorry, I look it up in dictionary, but still not sure about its meaning.

(2) You mentioned that PEP medications stay in the system less than a day and no residual effect even 2 or more days after the last does of medication.

    In this sense, is it safe to say that one's window period with HIV PEP medication can start from the day when the medication is discontinued 
    as those without PEP medication (4~6 weeks on combo test)? 

    If yes, I was wondering why it is often said that the use of HIV PEP medications would oppress virus replication, if infected, then blunt antibody 
    response and thus prolong window period to six months or even one year after exposure. 


(3) Dear Dr. Hook. there is a study (http://www.natap.org/2019/EACS/EACS_73.htm ) indicating later HIV diagnosis (median 3.8 years) after PEP medication
     I am confused and worried. Please kindly check it out. If PEP leaves our body within days, how could the HIV diagnosis be delayed for so long? 


(4) Dear Dr. Hook, I have used PEP TWICE
    (4.1) The first is the one I reported to you in the last letter where I took 28-day HIV PEP(Isentress and Combivir or Isentress and Tenofovir. Sorry, I forgot)
              in May, 2016I was then tested negative at 6 and 12 months after the exposure. 
 
      (4.2) 15 months later (August and September 2017, no exposure during the 15 months), I had other three new exposures. 
                 September 2017, I took PEP again, but this time I didn't complete the 28-day full course.
                 I took only 6-day-7-pill Triumeq (Triumeq is supposed to be taken once daily, but for the adjustment of medication timing, I took two pills of 
                 Triumeq at Day 3, and I stopped the medication at Day 7.)

     I have little idea of how the PEP 
     (First time in May 2016: 28-day Isentress and Combivir or Isentress and Tenofovir. 
     Second time in September 2017: 6-day-7-pill Triumeq )
     would affect my antibody responses and window period,if infected. 
     And little do I know what to do and how to test when the second-time PEP was not taken fully since few studies are about the INCOMPLETE use of 
     PEP. 
     
     I have no exposure since my second-time PEP (6-day-7-pill Triumeq). 
     After the use of the second-time PEP (6-day-7-pill Triumeq), the latest HIV RT PCR test was target not detected (limit 20 copies/ml) at 24 months and
       HIV Combo test  came back negative at 28 months. (The tests were taken in September 2019 and February 2020, respectively.)
    
       Dear Dr. Hook, given all the HIV PEP 
      (two times, different medications for the two times. First time in Mary 2016 is 28-day completed, and second time in September 2017 is 6-day-7-pill Triumeq)
       and given the test results, what do you think of my status?  Do you think the test results are conclusive?
       Or the PEP altogether could still potentially affect my system  and thus make the test results inconclusive? 
   
(5) Would the HIV PEP medications  affect the validity of HCV tests? 
       (first time in May 2016: 28-day Isentress and Combivir or Isentress and Tenofovir. Second time in September 2017: 6-day-7-pill Triumeq )
      
       My HCV test was negative at 27 months after the second PEP medication. 
     Is the HCV test result conclusive?



(6) Given I have had PEP twice, if I have new exposure now,  how long is my window period? Is it still 4~6 weeks? 


Dear  Dr. Hook, sorry, my English is not that good and I am worried. 
Please kindly kindly address my questions. Thank you very much !


Edward W. Hook M.D.
Edward W. Hook M.D.
12 months ago

Your extensive reply exceeds the recommended word limit for the Forum. Replies will be brief.  In reading your follow-up it appears that you have a misunderstanding about PEP and how it works.  PEP is recommended for HIV prevention following a high risk exposure and its activity is intended to be relevant for a single exposure/event.  It may reduce for risk for infection due to exposures which occur while taking PEP but that is not the reason it is intended to be used.  For persons who have continuing risks for HIV it is better tot o take daily preventative therapy _PrEP) rather than PEP following each high risk event

1.  Sorry this was not clear.  By the time 2 days (48 hours) had passed since your last dose of PEP, there would be no more protection from HIV infection due to the medication.

2. This statement if correct.  The reason that we worry that future antibody production would be delayed is not because of the effected of PEP drugs on new exposures but because any virus which might have been present while taking PEP (from the original exposure) would be slow growing and therefore lead to a delayed antibody response.

3.  This report has nothing to do with failures of PEP.  It indicates that persons who take PEP in this study had continuing risk for acquisition of HIV (and therefore might be better served by taking PrEP rather than PEP)

4. Your tests are conclusive.  Each time you take PEP you are taking medication related to efforts to prevent infection following a single exposure.  Taking PEP more than once does NOT reduce its effectiveness.  HOWEVER, if you feel you need PEP repeatedly I would suggest you talk with your doctor about taking PrEP on a daily basis rather than taking PEP repeatedly.  this is a personal decision but you should discuss your risks and need for preventative therapy with your own doctor or a local HIV specialist.

5.  PEP will not effect HIV tests.  Your result is conclusive.

6. Following and exposure and the decision to take PEP, testing for HIV should be taken using a combination HIV antigen/antibody ("duo") test 12 weeks after beginning PEP (8 weeks after finishing PEP)

I hope this is helpful.  EWH

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12 months ago
Dear Dr. Hook, 

Thank you for your reply.

Due to my limited English proficiency, I need to confirm whether I understand you correctly. 

You replied 

1. Given your reply  that by the time 2 days (48 hours) had passed since your last dose of PEP, there would be no more protection from HIV infection due to the medication. 

2. This statement if correct.  The reason that we worry that future antibody production would be delayed is not because of the effected of PEP drugs on new exposures but because any virus which might have been present while taking PEP (from the original exposure) would be slow growing and therefore lead to a delayed antibody response.


Here are my questions: 

 (1) The two points (especially those in boldface) seems contradictory to me. I am confused. 
       The first point indicates the effect of PEP would disappear after 48 hours since the last does. 
       The second point indicates the use of PEP would delay antibody response if infection occurred.
        I don't know HOW LONG antibody response could be delayed by the use of PEP medication. Is the delay just only TWO days (as you mentioned in point 1 )
       Then why is it often said the use of PEP could delay antibody response till 6 months or even one year?  

  (2)Dear doctor Hook,
        based on my inquiries above related to the effects of PEP,  could you please please tell me why you think my test results are conclusive.
        Can I be assured that I am not infected with HIV? 

       I took PEP twice.
     (First time in May 2016: 28-day Isentress and Combivir or Isentress and Tenofovir. 
     Second time in September 2017: 6-day-7-pill Triumeq ). 
     There were four exposures in between. 

       The last exposure occurred in September 2017, and the second-time PEP (6-day-7-pill Triumeq) was intended for the exposure. 
       After that, I have had no exposures. 

       The latest result on Combo test was negative at 28 months, 
       and RT PCR (limit 20 copies/ml) was target not detected at 24 months after the second-time PEP medication (6-day-7-pill Triumeq). 
       Is it safe to say that I am not infected with HIV? 

      I am afraid the PEP twice altogether would affect and delay my antibody response, if infected and PEP failed, and thus lead to FALSE NEGATIVE test results.
       considering the fact that I took Triumeq twice at Day 3 of the second-time 6-day-7-pill PEP course would raise the medication concentration and thus delay 
      antibody response for a longer while.

      Since there are no guidelines specifying clearly the window period for cases of INCOMPLETE use of PEP,
      I am especially worried about the fact my second-time PEP course is not completed: I stopped it early. I took only 6-day-7-pill Triumeq.   

 (3) Dear Dr. Hook, you replied "PEP will not effect HIV tests.  Your result is conclusive"  to my inquiry about HCV as question 5 in the last letter.  
       Is it a typo or ? Is my HCV test result conclusive? 

Dear Dr. Hook, please kindly address my questions. Thank you!
Edward W. Hook M.D.
Edward W. Hook M.D.
12 months ago

This will be my final reply.  Your questions have become somewhat repetitive and as I suggested earlier, it appears you have a misunderstanding of why PEP is good for some persons, why PrEP is good for others and why many persons really do not need either.  Explaining this is beyond the scope of this forum.  I suggest you read about it on the internet and then speak with your own health care provider to help you guide your own decision making. .Again, these final replies will be brief

1.You are once again missing the point.  The statements are NOT contradictory. You are once again, confusing the effect of PEP in preventing infection following an encounter which puts you at risk with the probability that while taking PEP, subsequent risky encounters might lead to infection.  PEP is designed to prevent infection AFTER exposure.   Suppression of viral growth from an infection occurring at the time of the encounter due to PEP could theoretically delay development of antibodies.  Rather than provide incorrect information, recommendations for HIV testing after PEP are conservative and for that reason, recommendations are that follow-up testing for infection following completion of PEP are that test results are NOT conclusive until 8 weeks following completion of pep (12 weeks after the exposure).  Statements that PEP could delay antibody production for 6 months or a year are incorrect and sound to me like the sort of misinformation that is found on the internet.

2.  Also repetitive.  You have tested more than 8 weeks following completion of PEP.  Results of tests taken more than 8 weeks following completion of PEPare conclusive.    Both your combo results at 28 moths following completion of PEP and your RNA results at 24 months prOVE that you are not infected by the exposures which led you to take PEP.  Believe your results.  You do not have HIV.

3.  Repetitive.  Your HCV test results are conclusive

This completes this thread.  I trust you will not return to the Forum with further repetitive questions.  If you do , your questions may be deleted without a response and without return of your posting fee.  EWH

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