Q and A


Chances of infecting partner if I have an undetectable viral load?

I have been positive for three years now and started treatment two months ago. If my viral load is undetectable can I still infect someone? Are the chances of infecting my partner still the same if we had unprotected sex?


Thank you for your questions.

In 2018, the answer to your question is a clear “no”.

Having an undetectable viral load makes HIV untransmittable. The evidence for this is at this link:

This was already believed by some experts in 2008 (when this question was first answered). The¬†statement on behalf of the Swiss Federal Commission for HIV and AIDS¬†authored by four of Switzerland’s foremost HIV experts said that an HIV infected person on ART with an undetectable viral load cannot transmit HIV through sexual contact. This information was published in the Bulletin of Swiss medicine in January 2008 was largely based on data from heterosexual sex.

See this factsheet on the Swiss Statement.

Note: This answer was updated in February 2018 from a question first posted online in February 2008.


  1. Ntkozo

    Hi Admin
    I have been taking arvs for more than seven years with undetectable viral load. Recently we had sexual contact with my boyfriend. I am worried, are any chances that he might infected?

  2. Malakia Halweendo

    Thank you for the information.

  3. Lisa Thorley

    Hi Nthabi,

    No one can say for definite that babies born to HIV positive mothers will be negative if their mothers are undetectable. Therefore this is why babies need to take medication, and why testing is so important. However, the risks are dramatically reduced. For more info, please see here:


    In response to your other question. No you can’t transmit HIV to your baby if you have condom-less sex with your partner.

  4. nthabi

    Hi am HIV positive and pregnant I’m on treatment. Can I infect my baby with HIV even if the viral load is undetectable?

  5. Lisa Thorley

    Hi Naledi,

    Because you’re on meds and have an undetectable viral load, the risk of transmission is close to zero. Please see here for more info:


    With regards to telling your boyfriend about your status, for many people this can be difficult. What you could do is ask him what his thoughts regarding HIV. Having the answers to his possible questions may also help. How you do it though, or if you do do it is a personal choice.

  6. Naledi

    Hello Admin
    I’ve been HIV for 2 years now and my viral load is below detectable limit. I recently slept with my bf without a condom. Is it possible for him to contract the virus? The aim was to let him know and everything happened so fast and again I still want to tell him about my status but I’m afraid he’s going to leave me for not telling him on the on set

  7. Lisa Thorley

    Hi Cindy,

    Please see the above post and Q6 here:


    The Following guide will also help:


  8. Cindy

    I’ve been diagnosed HIV from 2010 been on treatment since then, I’ve been taking my treatment consciously. What worries me is that my boyfriend of 2 years knows about my status and he’s HIV negative and we having unprotected sex he also wants a child since he doesn’t have one. Is it safe for us to have one.

  9. Lisa Thorley

    Hi Thandi,

    I can’t tell you how to tell your partner about your status, this is because we’re all different and how people react to the news that someone is positive varies. However, have you tried bringing up the issue of HIV into conversation? If you have what was his reaction?

    With regards to transmission, as the data from the PARTNER study explains, the risks are close to zero. Please see here:


    Also, even if there were a risk, if he’s insisting on not using condoms, then he needs to be prepared to take risk of contracting HIV.

  10. Thandi

    Hi admin
    I am HIV positive for 9years now,i have disclose my status to my mom and other friends.But now i am in a new relationship now almost 6months,now problem is my partner do not want to use condom its been 4months now without using protection am on ARVs n my viral load is undetectable ….He does not know about my status and am worried about this