Q and A


Will PEP reduce the risk of infecting my negative partner?

I am a HIV positive gay man and my partner is negative.

I take my meds and my viral load is undetectable. My partner and I always use condoms. I still worry that I could infect my partner.

Realistically, how safe is my partner? Is sex with me risky for him? (He is active, I am passive). Also, can PEP helps to prevent my partner from being infected?


There are many couples (both gay and straight) who are in a similar situation as you.  Sero-different couples (where one is partner positive and the other is negative) can have a good and healthy relationship for many years.  There are many factors on how HIV is transmitted and you can find all the information at this link

Currently there is no cure or vaccination for HIV, even though there are many researches and trials that are pursuing this subject matter. These trials can take many years before the data is collected and analysed.  The duration of the trial depends on the findings – at times the trial runs shorter than expected and at times it takes longer.  We do not know how long these trials will take before they are publish.

The results from studies showing the dramatic impact on reducing risk of transmission when the positive partner is undetectable have mainly been from heterosexual couple who have low rates of anal sex.

In general, the risk to your partner will already be dramatically reduced compared to if you were not in treatment, but there is little data to say how low this risk goes.

It may go down very close to zero, but future studies are hoping to answer this question.  Sexual transmission is still quite difficult, and being on treatment makes this even more so. So these recent studies are particularly important for people who have a negative partner. If you are continuing to use condoms – always a good idea – then you can relax about the odd time when a condom may break or slip off.

The actual risk will relate to other factors. Insertive sex is generally a lower risk than receptive sex. Your treatment is likely to have reduced the viral load in the tissue in your anus and the related mucous there. If you partner is circumcised, then this will also make HIV slightly more difficult for him to catch as the insertive partner.

So while no-one will ever be able to say the risk is zero (you can not prove a negative) it would probably be very hard for him to catch HIV from you even if this was something to set out to do.  It is very unlikely that your partner will catch HIV while your viral load is undetectable especially if you continue using condoms.

PEP (post exposure prophylaxis) is a term used for taking HIV drugs after a possible exposure to reduce the risk of infection.  PEP usually involves taking a combination of three HIV drugs for one month and you also need to be aware of the side effects of these drugs.  Please take a look at our link for Q&A section based on PEP.


  1. Lisa Thorley

    Hi Jay,

    For info about PrEP, and what it is, please see here:



  2. jay

    I’m gay, receptive and hiv neg. I have heard from friends that the use of Prep could keep my status that way even if i played bareback, is this true?

    My doctor has suggested the use of Atripla instead of Prep, is Atripla more effective.

    Is my chances of contracting the virus whilst on Atripla, significantly reduced?

  3. Angelina Namiba

    Dear Nolu
    One of the benefits of ARVs (antiretroviral treatment for HIV), is that it dramatically reduces the risk of passing on HIV to the negative partner. It is also the main way of preventing transmission of HIV to the unborn baby. As a result, many people living with HIV in sero-different relationships (where one partner is positive and the other is not), have and continue to have healthy HIV negative babies.
    There are a number of conception options available for couples like you. These include options where there is zero risk of passing on HIV to your husband.This is where you can self inseminate with your partner’s sperm. For more information on these options, please follow this link to our guide to HIV, pregnancy and women’s health. The guide also answers a lot of general questions you may have around planning your pregnancy.
    In response to your question, it is possible to conceive naturally. This is because, although there is a small risk of passing HIV on, this risk is dramatically reduced by a number of factors including; if you are on treatment and have had an undetectable viral load for more than 6 months. Please follow this link to our guide to the Swiss Statement which explains in detail the other factors that need to be present to further reduce the risk of transmission.
    It is also important that you and you husband discuss your plans to have a baby, with your doctor as s/he will be able to advise you on how to do this in the safest way possible.
    Good luck with your future plans.

  4. Nolu

    I am on ART and my viral load is undetectable. what are the chances that my hiv negative hubby can get infected if we stop using condoms? We want to have a child together.

  5. Simon Collins

    This is a perfectly reasonable question but while it is easy to ask there is actually no data estimate this from. Nearly all studies that have shown the positive impact of treatment on reducing transmission (by reducing viral load to undetectable) have been in heterosexual couples who report vaginal but not anal sex. So while your partner is likely to be much less infectious on treatment compared to not being on treatment, we can;t put a figure on the remaining risk. There are sufficient different differences between anal and vaginal sex for this to be important. This is one of the questions that the current PARTNER study is looking to answer. This study is looking for couples in exactly your situation and it you are near a study site, please consider you and your partner asking for more information.

    Please see the new i-Base guide to HIV testing and the risk of sexual transmission. This explains and discusses this in more detail.

    For example, the factors at this link would be important to think about.

    Your risk will be related to your partners viral load in the mucosa in his bottom, whether you are circumcised, how long and how rough the sex is and your whether you are genetically more susceptible to catching HIV.

    I’m sorry that this answer is not as straight-forward as your were probably hoping for.

  6. Mike

    My partner is HIV+. He is on meds (Atripla) and has an undetectable viral load. I am negative. He and I have fairly frequent intercourse without condoms. I am always the top. How great is my risk to contracting HIV being in my situation (me being the negative top and him being the positive bottom)?