Is 4 weeks enough?

Hi there

I can't really believe I'm back here again, but I am. On the 7th July, just over 11 weeks ago, I had sex with a man using full protection for oral and insertive/receptive anal sex. However, I (very stupidly) used baby oil as a lubricant and my condom broke as I was performing insertive sex. It was a big rip, leaving most of the penis exposed.

About 54 hours later I went to the clinic and was put on a 4 week course of PEP. My first question is;

1. How reliable is the drug? I was on Truvada and Kaletra. Hopefully I followed the course correctly and didn't miss any doses. I understand it is very hard to measure, but what are your thoughts on the effectiveness of PEP? I've read on here that it is 87% reliable, but the doctors at my local clinic have told me they think it is completely reliable, having given it to 2000 people and never having had anyone seroconvert. Do you think it's likely that the PEP hasn't worked in my body?

2. Secondly, I wanted to ask you about the chance of being infected after insertive anal sex. Is there a percentage risk?

3. I have tested at 4 weeks after my last dose and the results were negative. How reliable is this test? Obviously I will test at 3 months, but having to wait and extra month due to the PEP course is proving really difficult for me.

I am developing some sort of illness. I have had a very very tiny pain in my throat for a week now, as well as being very heavy headed and feeling a little sick. Tomorrow is my first day as a fresher at university, and I have a busy freshers week ahead, a week that is meant to be 'the best of my life'. But I can't stop thinking about this... I should feel relieved after having taken PEP, but is it effective? And how reliable is a 4 week test?

Sorry for the long question.

[Edward W Hook, MD]

Welcome to this forum.  Before I get directly to the questions you have asked I need to make several points.  The first this is the STD Forum and your question belongs on the HIV Prevention Forum.  I will therefore provide just a single answer- there will be no follow-ups. If you have further questions you need to use the correct site.  Second, in preparing to answer your questions I reviewed some of the over 40 other posts you have made on other MedHelp sites.  Coming from my review, I have the sense that you tend to be quite concerned about such unprotected exposures, more so in my opinion than is warranted, and that it appears that in the past you spent a lot of time comparing different internet sites of information.  For that reason I will point out before I answer your questions that we do not debate other internet sites on this site and that the internet is not a very good place to get such information as there is so much variability in the quality and veracity of the information to be found there.  You cannot and should not believe everything you see on the net.  Finally, unless you know otherwise, it is important to point out to you that you do not know that the person you had sex with had HIV unless you asked him and the fact is, most people, even persons in so-called "high risk groups" do not have HIV.  Thus the chance that you were even exposed to HIV in the exposure you mention is low, probably less than 1 in 10 and as you'll see below, even if your partner had HIV, the chance that you acquired infection if he was infected is low.

Now let's address your questions:
1. How reliable is the drug? I was on Truvada and Kaletra. Hopefully I followed the course correctly and didn't miss any doses. I understand it is very hard to measure, but what are your thoughts on the effectiveness of PEP? I've read on here that it is 87% reliable, but the doctors at my local clinic have told me they think it is completely reliable, having given it to 2000 people and never having had anyone seroconvert. Do you think it's likely that the PEP hasn't worked in my body?

Your chance of infection IF your partner was infected (he was probably not) from a single insertional rectal exposure is statistically about 1% without PEP.   PEP is highly effective and the best protection that an exposed person can have for reducing their risk of infection, if exposed.  The studies that show the effectiveness of PEP, like all good scientific studies provide an ESTIMATE of the likelihood of an effect.  The estimated effect of studies of PEP is, conservatively, that they are 90-95% effective in preventing infection, IF the medication is take as directed.  (Fewer than 50% of persons who take PEP take the entire course of medication as directed).  Thus, be taking the PEP, you further reduce the already low (less than 0.1%) risk that you will be infected (assuming a less than 10% chance your partner was infected and a 1% chance of infection from your exposure if he was infected) by more than 90% to less than 0.01% (less than 1 in 10,000).  Following this line of thinking, if I were you, I would assume that your chance of being infected, based both on your history, your PEP and your test results is very, very low and if I were you I would not worry further.  


2. Secondly, I wanted to ask you about the chance of being infected after insertive anal sex. Is there a percentage risk?
See above. The statistical estimate that you would be infected with a single unprotected exposure to an infected partner is about 1%.

3. I have tested at 4 weeks after my last dose and the results were negative. How reliable is this test? Obviously I will test at 3 months, but having to wait and extra month due to the PEP course is proving really difficult for me.
This is very strong evidence that you are not infected.  I would not be worried if I were you.

I hope these answers are helpful.  EWH

[greendiff92]

Just to clarify, the STD I am talking about is HIV