Can HIV be transmitted via oral sex?

Dear Happy but Worried,  

In general, oral sex has a lower risk of HIV (human immunodeficiency virus) transmission compared to anal and vaginal sex. While HIV transmission through oral sex is rare, individual risk factors like having open wounds in your mouth, performing oral sex on someone with HIV instead of being the receptive partner, and having untreated infections can increase the risk of transmission.  

How is HIV transmitted? 

HIV is transmitted through direct contact with blood, semen, pre-ejaculate, breast milk, rectal fluids, and vaginal fluids from a person with a detectable viral load. For transmission to occur, these fluids must enter the bloodstream through a mucus membrane (such as the vagina, rectum, mouth, or tip of penis), open cuts or sores, or direct injection into the bloodstream. When it comes to sexual transmission, HIV is commonly transmitted through anal and vaginal sex.  

Can HIV be transmitted through oral sex? 

While HIV can be transmitted through oral sex, it has a much lower risk of HIV transmission compared to anal and vaginal sex. This is because the enzymes in saliva can inhibit the transmission of the virus. That said, while HIV transmission through oral sex is rare, some factors can increase the risk of transmission. These include: 

• Cuts, bleeding gums, and sores: Open wounds in a receptive person’s mouth make it easier for the virus to enter the bloodstream. 
• Ejaculation: Ejaculating into a partner’s mouth during oral sex may increase the risk of infection. 
• Other sexually transmitted infections (STIs): Some STIs such as herpes can cause lesions and sores. This can weaken the mucus membranes in the mouth and throat, increasing the risk of HIV infection.  
• Receptive oral sex: Performing oral sex (your mouth on their genitals) on someone with HIV has higher risk of transmission compared to receiving oral sex (their mouth on your genitals) from someone with HIV. In rare cases, being bitten by a person with HIV may also cause HIV transmission if the skin breaks and there’s contact between blood, broken skin, and mucus membranes. 
• HIV levels in genital fluids: HIV levels in vaginal fluids tend to be highest around the time when a person is menstruating because cells carrying HIV are shed from the cervix. Performing oral sex on a person with HIV when they’re on their period slightly increases the risk of HIV transmission. This can also happen if a person with a penis has urethritis, as inflammation can cause more virus particles to be shed through semen.  

How can you reduce the risk of HIV transmission? 

It’s recommended to avoid sexual activity if you're in a “high risk” period such as during a genital herpes outbreak. At other times, practicing safer sex can reduce the risk of infection. Using condoms and dental dams during oral sex can help to protect you and your partners. It's also recommended to avoid brushing or flossing your teeth immediately before giving oral sex because it could give you tiny cuts or make your gums bleed, which increase the risk of HIV transmission. 

Getting tested for HIV and other STIs can provide you and your partners with information that can help you to avoid getting or transmitting HIV. If you don’t have HIV and your sexual partner has HIV, taking pre-exposure prophylaxis (PrEP) can reduce the risk of HIV infection. If you think that you may have been exposed to HIV, starting post-exposure prophylaxis (PEP) can help to prevent infection when taken within 72 hours. If you or your partner has HIV, getting and staying on HIV treatment can help to reduce the amount of virus in the blood and prevent transmission.  

Have fun and stay safe!