If you're on treatment and have immeasurable virus levels, you cannot transmit HIV when having sex, even if a condom is not used. The safest thing you can do, if you want to avoid getting HIV yourself, is to have sex with somebody how have undetectable HIV.
When someone with HIV is being treated and takes their medication properly, the amount of virus in their blood decreases so much that it can no longer be measured. The person then has immeasurable HIV. A person with undetectable HIV cannot transmit it to another person when having sex, even if a condom is not used. The so-called Partner II study, the results of which were presented at the International AIDS Conference 2018 in Amsterdam, confirms that undetectable HIV equals untransmittable HIV. The study involved 783 gay couples from 14 European countries, where one partner lives with undetectable HIV and the other without HIV. The couples reported just over 77,000 condomless anal intercourse, without a single case of HIV transmission within those couples. The study was a continuation of the Partner I study, which included both same-sex and different-sex couples and examined both vaginal and anal intercourse. In Partner II, only same-sex male couples were surveyed. Overall the studies confirm that untransmittable HIV is not transmitted. Undetectable HIV is untransmittable HIV. U = U.
Undetectable HIV cannot be transmitted when having sex, even if a condom is not used. However, using a condom is still important as it protects against transmission of STIs such as chlamydia, gonorrhea and syphilis. If you are uncertain about your own or your partners’ HIV status, the condom is also an effective protection against the transmission of HIV.
Read more about O = O, or U = U (undetectable = untransmittable), here (opens in new tab)
Read more about the Partner II study here (opens in new tab)