Whether you prefer to give, receive, or both, blow jobs are a bedroom staple. They’re as common as gay guy names like “Matt” or gay guy jobs like “brand manager”. Sometimes – if you’re a side, or just not in the mood for butt stuff – they’re even the main event!
We know that condomless anal and vaginal sex are a risk for HIV transmission if the positive partner has a detectable viral load. But is oral sex a risk for HIV?
We’ve got the answers! Read on for our guide to the science behind HIV transmission and fellatio.
How HIV transmission works
Before we get into oral sex, a quick recap on some HIV basics.
HIV transmission happens when infectious bodily fluids from an HIV-positive person get into the blood of an HIV-negative person. Infectious fluids are things like blood, semen (including pre-cum), and anal fluid. This can happen directly, for example by sharing equipment to inject drugs.
Fluids can also get into the bloodstream through mucous membranes. These are warm, wet tissues in places like the genitals or anus. Transmission can happen when infectious fluids meet these tissues during condomless anal or vaginal sex.
Mucous membranes in the mouth are different, and HIV transmission is much less likely through them. This is because, unless someone has cuts or sores, oral tissue and saliva work together to provide some antiviral protection against HIV.
Is oral sex an HIV risk?
Insertive oral sex (i.e. getting a blow job) is not an HIV transmission risk. Receptive oral sex (i.e. giving head) is a very low risk. It’s not zero risk, but HIV transmission this way needs some very specific circumstances to happen. These are:
- Your partner has a detectable viral load (in other words, they have undiagnosed HIV or know their status but are not on HIV treatment)
- Your partner cums in your mouth
- You have open cuts or sores in your mouth (e.g. from poor oral health, recent dental work, or if you’ve just brushed/flossed your teeth)
Remember that if someone has an undetectable viral load, they cannot transmit HIV through sex.
How we research HIV risk
Researching HIV risk for oral sex is challenging. This is because people who report oral sex are almost always having other kinds of sex as well. In other words, it’s very rare that someone who contracted HIV had oral sex as their only risk factor.
Studies of this type also rely on people self-reporting the kinds of sex they have, which isn’t completely reliable. Because of the stigma around condomless anal sex, it’s likely that people under-report this – which makes it hard to get accurate data.
What does the science say?
Published research shows that the HIV risk for oral sex is very low. One paper from 2008 analyzed 10 previous studies and found a “low but non-zero transmission probability.” Three of the studies in their survey found zero risk at all.
Another paper in 2014 surveyed research to calculate HIV risk for different activities, grading these by risk per 10,000 exposures (so, how many transmissions would happen if you were exposed to HIV this way 10,000 times). Blood transfusions had a risk of 9,250 transmissions per 10,000 exposures. With oral sex, researchers estimated somewhere between 0 and 4. They concluded “although HIV transmission via oral sex is biologically plausible, we are unable to provide a precise numeric estimate.”
What does this mean for me?
Oral sex isn’t something to worry about when it comes to HIV transmission. However, you can make this low risk even lower by:
- Avoiding brushing or flossing your teeth for at least a half hour beforehand
- Not having your partner ejaculate (cum) in your mouth
- If you have mouth ulcers or have had recent dental work, using prevention tools like condoms or PrEP.
Preventing other STIs
While condomless oral sex is low risk for HIV transmission, it can still transmit STIs like chlamydia, syphilis, and gonorrhea both ways. That means you can get an STI in your throat from performing oral sex on someone, or an STI in your genitals if someone giving you a blow job has one in their throat.
Condoms can help prevent STI transmission during oral sex. DoxyPEP can also lower risk for chlamydia and syphilis, but it doesn't remove risk. Whatever STI prevention options you choose, regular testing and treatment (if needed) are essential for keeping you and your partners healthy! This is important because not all STIs have symptoms.
To learn about other types of oral sex, check out the Freddie Guide to: Rimming.
