Oral Sex and HIV Transmission
Oral sex is considered a very low risk practice in regard to HIV transmission.
In the case of oral sex with a HIV positive partner, the risk of transmission is lowered even further if the HIV-positive partner is on treatment and has a low viral load, and/or the HIV-negative partner is using pre-exposure prophylaxis (PrEP).
The risk can increase if there is cumming in the mouth, and if there are cuts or ulcers in the mouth, or the presence on another STI. Even in these instances it is still regarded as low risk.
Caution should be taken with this in mind, particularly directly after dental surgery or immediately after flossing.