While anal sex is often taboo, it is practised by a large number of people of all genders. When done without condoms, anal sex can carry a high risk of HIV transmission for both partners.
The receptive partner is at greater risk because the lining on the anus is thin and may tear during anal sex, allowing semen or blood to enter the body.
The anus
The anus is surrounded by delicate tissue, and it’s important to protect this area of the body when having anal sex. Using anal lubricant helps reduce friction between the penis and the anus, which can help prevent irritation. Also, avoiding sexual touching on the anus altogether can lower the risk of an infection.
Anal sex poses a higher risk of passing on STIs than many other types of sex, including vaginal sex and oral sex. This is because the lining of the anus is thin and can be easily damaged during penetration. Penetrative anal sex is especially dangerous for women, who may be at increased risk of developing a fistula in their rectums. This condition can lead to fecal incontinence and other serious complications.
HIV is most often transmitted through unprotected anal sex in gay men, according to research published in the Journal of Sexual Medicine. Being the receptive partner in an unprotected act of anal sex increases one’s risk of HIV transmission by 10 to 25 times compared to being the insertive partner.
HIV transmission in anal sex is less likely to occur if both partners use protection during anal sex, such as condoms and oral or vaginal lubricants. In addition to protecting against anal sex-related infections, people can take other steps to stay safe, such as getting regular Pap smears and bowel movements and taking pre-exposure prophylaxis (PrEP) to reduce the risk of acquiring STIs.
The urethra
During anal sex, both partners can be at risk of contracting HIV. However, the receptive partner may have a higher chance of getting an infection due to the lining on the inside of the anus being thin and susceptible to tearing during intercourse. Additionally, during anal sex, rectal fluid can enter the urethra or small cuts, scratches, or open sores on the penis that are vulnerable to HIV infection (2).
The receptive partner of anal sex may also be at risk for passing bacteria from the anus to other parts of the body, such as the genitals, mouth, eyes, or fingers. This is more likely if the receptive partner has a fistula (a hole or tear in the anus lining), which can allow stool to enter other areas of the body (3).
Penetrative anal sex can increase the risk of passing STIs such as hepatitis A, hepatitis B, herpes, and HPV, and the risk is even greater for people with a fistula (4). Additionally, sex toys and other accessories that make contact with the anus can spread bacteria around the area to areas of the body not intended, such as the genitals, hands, and mouth.
People who have anal sex without protection should talk to their doctor about using a condom and taking post-exposure prophylaxis if they are at high risk for HIV infection.
The sphincter muscle
The sphincter muscle that controls feces is located in the anus and tightens after we have a bowel movement. If this muscle is weak, it can lead to anal fistulas. This condition is painful and requires surgery to repair. It can also increase the risk of HIV transmission through anal sex.
Because the anus and rectum do not have the cells that create the natural lubrication of the vagina, there is a higher chance of friction-related skin tears during penetration. These tears can introduce bacteria to other parts of the body. Lubrication helps reduce this risk and can be achieved by using a water-based lubricant. It is also important to change condoms when moving from anal sex to vaginal sex to avoid introducing different types of bacteria.
For anal play to be enjoyable, it is important that both partners are sufficiently aroused. This will relax the sphincter muscle and help prevent tearing. It is also recommended that both partners wash their hands before penetration.
Some people enjoy stimulating the anus with a finger or sex toy. While this may be pleasurable, it carries a greater risk of infection than other forms of sexual penetration. Using a lot of lube and taking anal penetration slowly can help minimize the risk of injury and transmission of bacteria. It is also important to wash sex toys frequently and to clean them between uses.
The vagina
The anus is softer than the vagina and doesn’t have as much natural lubrication. This can make it easy for the tissue to tear, which can open the door for viruses and bacteria like HIV, hepatitis C, and human papillomavirus (HPV) to enter the bloodstream. HPV can lead to genital warts, anal cancer, and other health issues.
HIV transmission risks vary by sexual activity, but unprotected anal sex with someone who has HIV poses the highest risk of infection for both the insertive partner and the receptive partner. People with HIV who inject drugs, such as heroin, also face a higher risk of HIV infection because they may pass the virus through rectal fluid.
Condoms are the most effective way to protect against anal sex and other sexually transmitted infections. You can use an external condom that slips over the anus, a dental dam, or extra-thick condoms designed for anal use. You can also use lubricants to help prevent tearing. Sniffing poppers, which are nitrite-based inhalants, can relax the anal sphincter muscles and make intercourse more comfortable. However, it’s important to avoid rubbing the anus because this can increase the risk of tears. If you’ve had unprotected anal sex, your doctor can prescribe a medication called post-exposure prophylaxis (PEP) to reduce the chances of infection. You can also get PEP from a community health center or through your insurance.
