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. Sibongile •

    I slept with my boyfriend for about 10min without using a condom, will I have infected him?

  2. Lisa Thorley •

    Hi Thobekile,

    What study are you involved in?

    If the guy is on treatment and his viral load is undetectable, the risk of transmission is close to zero. For more info please see above.

  3. Thobekile •

    I slept with someone who is HIV positive. I’m on the study for a HIV Vaccine. Its been 7days. Do you think I may be infected? The guy is on treatment.

  4. Lisa Thorley •

    Hi David,

    Please see Q1 here:

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

  5. David •

    Can someone telll me if I will be okay infected with hiv, I had an exposure on 28night of February with an hiv possitive person and this person was not on Arvs , and this person said she has been infected since 2 months before I slept with her,so I started the treatment of Afavirenz and Emtevir Drugs now,I have finish this drugs since march 31 and now it is April 17 and I have test twice on the 15th of April, i have had no symptoms and am still testing nagative what is the risk that I will be infected after I test again to make it 3months.i need help please.also as the girl said she said the dr said her immune system is okay.

  6. Lisa Thorley •

    Hi Luke,

    Please see Q1 here:

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

  7. Luke •

    Hi,

    I had a protected one night stand with a lady I met at a bar late January 2017, the condom did not break, slip or anything, but I am a bit worried. Also, I managed to quiz her on her sexual history, she said that she did not have sex in over 6 months, before our encounter, and that she did not have any “diseases” and that she is on contraceptions.

    I know I am being paranoid, but one can never truly know.

    Also, is it too early to get an HIV test? is been more than 2 months since the encounter.

    Regards
    Luke

  8. Lisa Thorley •

    Hi Boston,

    If the person you had sex with is on medication and their viral load is undetectable the risk is close to zero.

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

    If they aren’t on medication, then yes, your may have contracted HIV. Therefore, you will need to test.

  9. boston •

    I slept with someone who is HIV positive. We didn’t use a condom. Should I be worried?

  10. Lisa Thorley •

    Hi Monicah,

    Starting PEP now would not work, this is because it needs to be taken within max 72hrs after a possible risk.

    If the man that you had sex with is HIV positive, if he’s on medication and his viral load is undetectable then the risk of transmission will be close to zero. Please see here:

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

    If he is HIV positive and not on medication, then yes, your may have contracted HIV. Therefore, you will need to test.