Q and A

Question

Can I have sex with someone who is positive and not catch HIV?

16 January 2018. Related: All topics, HIV transmission.

Answer

Answer: Simon Collins

Yes, there are lots of ways to make sure HIV is not transmitted during sex.

  1. One of the easiest and most effective ways is just for the HIV positive partner to be on treatment. An undetectable viral load makes HIV untransmittable. (See: The evidence for U=U).
  2. Another relatively recent option is for the negative partner to use PrEP. This is an oral drug that when taken as prescribed is highly effective. (See: UK guide to PrEP).
  3. You can use condoms which are an effective barrier against HIV (and other STIs). Condoms need to be used carefully, preferably with plenty of lube. (See: How to use a condom (male and female).

HIV is a much less infectious virus than many other sexually transmitted infections (STI’s).

Even without a condom, the risk from a single exposure is less than, for example, 1 in 300. The actual risk becoming infected varies depending on many factors. These include the type of exposure, whether the other person is HIV positive, how high or low their viral load is, the duration and roughness of the sex etc.

If the partner is HIV positive, then viral load is the most important factor. The PARTNER study reported zero HIV transmissions after 900 couples had sex more than 58,000 times WITHOUT condoms. In this study undetectable viral load was defined as being less than 200 copies/mL.
https://i-base.info/qa-on-the-partner-study

Risk factors for penetrative sex without a condom with someone who has a very high viral load could be as high as 1 in 10 (10% risk). But the risk is effectively zero with someone who is taking treatment and who has an undetectable viral load.

This question was updated in January 2018 and November 2016 from an original answer posted in June 2007. i-Base no longer answers individual questions about HIV transmission and risk. (See: Question 1 at this link).

209 comments

  1. J jones •

    I had sex with an HIV positive.I didn’t know that she was HIV and she didn’t know her status as well. I used a condom then in the last minute I took off the condom to ejaculate in her. I became worried then I insisted that we should go for HIV test. The following day after sex I went for the test which came out negative but her she was scared.after two days she went just to find that she was positive.is it automatic that I got HIV by ejaculating in her.

  2. Lisa Thorley •

    Hi Rick,

    When someone has an undetectable viral load the risk of transmission when not using condoms is close to zero. For more info, please see here:

    http://i-base.info/qa-on-the-partner-study/

  3. Rick •

    Hi! On June 29 I had sex with a hiv positive (undetectable) person. We had unprotected oral sex (he was the recipient) and he didn’t ejaculate in my mouth. We also had anal sex (with condom) where we used both of our salivas as lube. When he came he wasn’t inside me, and he had the condom on, which worked just fine (his semen was stuck inside the condom, as we could see it). Have I somehow been exposed to the virus? Am I at risk of becoming positive? How long should I wait to get tested? Thank you!

  4. Lisa Thorley •

    Hi Sally,

    If he wasn’t on treatment, then yes you are risk. Therefore, you will need to test. Even if he tested negative in 2016, his viral load could still be very high. It will though have been detectable when you were having sex.

  5. Sally •

    I had unprotected sex with an infected person twice. He didn’t know he was infected until we got together in 2017 but tested negative in 2016, which means he has a low viral load? I’m I still at risk?

  6. Lisa Thorley •

    Hi Alan,

    Please see Q1 here:

    http://i-base.info/qa/what-are-the-most-asked-questions

  7. Alan •

    If the girl is somehow infected and the sex wasn’t rough and the guy dosent eject his semen inside her than is there a less chance of infection

  8. Lisa Thorley •

    Hi Pjay,

    If the person you had sex with is on treatment and has an undetectable viral load, the risk is close to zero. If however they aren’t on meds, or their viral load is detectable, then yes, you are at risk. If you are unsure you will need to test.

  9. Pjay •

    I had sex (unprotected) just once with an HIV positive person, am I safe from the contacting the virus?

  10. Lisa Thorley •

    Hi want to love.

    If he’s on meds and has an undetectable viral load the risk of transmission is close to zero. Please see here for more info:

    http://i-base.info/qa/what-are-the-most-asked-questions