Q and A


What is the risk of HIV transmission through oral sex?

First of all my thanks to everyone at i-Base!

I have a question regarding transmission. I am HIV positive and have a low viral load (under 250) and am not yet on medication. I always use condoms for anal intercourse but my questions relate to oral sex.

From what I’ve read, the risk increases:
• if the insertive partner has a high viral load.
• if the receptive partner has infections in the mouth or cuts, gum disease, has had recent dental work etc
• if the receptive partner takes semen in the mouth

Also, if the HIV positive receptive partner has blood in the mouth – could they possibly infect a negative partner

I can only find terms such as ‘low risk, very low’ but this all seems subjective. Low compared to the risk of unprotected intercourse doesn’t really mean much. Does that mean that with an undetectable/low/mid/high viral load that condoms should always be used or that if you avoid the higher risk scenarios unprotected oral sex is considered safe? I guess it all relates to the level of risk someone is willing to accept so I was hoping you might have some data e.g. percentage risk per act etc.

I read that there was a Spanish study reporting no seroconversions from 19,000 exposures over 10 years in serodiscordant couples and other reports saying that up to 5% of infections could be attributed to oral sex. Are there any recent studies to clarify the level of risk and also which reports would you regard as the most accurate?

I’ve recently met a great guy and it’s come to the point that I want to disclose my status. I’m hoping this might allow us both to put the level of risk into perspective.

Many thanks in advance and best wishes


Thank you for your question.

HIV is not easily transmitted by oral sex – and it probably needs ALL the factors you listed. For example, the positive partner would have to have a very high viral load AND the negative partner would have to have oral concerns like bleeding gums or recent dental work.

There are no cases of people catching HIV from receiving oral sex (from a person who has blood in their mouth). This is zero risk.

Your viral load is currently very low, which make any risk incredibly low. If your viral load was undetectable on treatment, the risk would be zero for all types of sex.

In 2018, HIV treatment is routinely recommended for anyone who is HIV positive. This, together with the evidence that undetectable viral load prevents transmission has dramatically changed more discussions about HIV risk. A review of this evidence is at this link:

This booklet has more information about sexual transmission, including a section on oral sex:

For any further information please contact us via the website, e-mail or through the treatment information phoneline (Mon-Wed 12-4pm).

Best wishes for the future with your new partner.

Note: This answer was updated in February 2018 from a question first posted online in April 2010.


  1. Josh Peasegood

    Hi Nancy, no, this is not how HIV is transmitted. There is no risk.


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