“Some Ways You Can Contract HIV and the Risk of Each One.”

Hi, this is Dr. Becky Kuhn. I’m a physician who specializes in HIV/AIDS. Welcome to “Some Ways You Can Contract HIV and the Risk of Each One.”

People often ask us which sexual practices have a higher risk of HIV transmission and which have a lower risk. This video will discuss the estimated risk of HIV transmission for mother-to-child transmission, needle sharing, and for some common sexual practices.

First, let’s cover some of the basics. HIV is present in an infected person’s blood, an infected man’s ejaculation fluid called semen, an infected woman’s vaginal fluids, and breast milk. HIV is not found in significant quantities in tears, sweat, or saliva. HIV spreads when one person’s body fluids come in direct contact with another person’s mucous membranes. Mucous membranes are the wet tissue found on parts of the body like the inside of the penis, vagina, anus, mouth, and nose or the surface of the eyes. When two people have sex and exchange body fluids, HIV may spread from one partner to the other. When injection drug users share needles, HIV may be transmitted between them. And when a woman infected with HIV gives birth to or breastfeeds a child, HIV may be transmitted to the infant.  

With that overview in mind, let’s now discuss the estimated risk of HIV transmission for mother-to-child transmission, needle sharing, and for some common sexual practices. It’s important to realize that these numbers are just estimates based on the currently available scientific information. The risk of contracting HIV from a partner will vary at different times during their infection. A person who has contracted HIV is most likely to transmit HIV soon after they have acquired the virus, which is known as the period of primary HIV infection. The numbers here are estimated average risks, and the risk of transmitting HIV can be increased or decreased by many other things. For example, for sexual contact, if either or both partners have other sexually transmitted diseases, the risk of HIV transmission will be increased.

Mother-to-Child-Transmission: 25% Without Treatment (1 in 4 Chance) 

Worldwide, mother-to-child transmission is one of the most common ways that HIV is transmitted. If a woman is HIV positive and becomes pregnant, there is a risk that her child will contract HIV during the pregnancy or more commonly during childbirth or while breastfeeding. If an HIV positive woman takes no steps to protect her child from HIV and does not breastfeed, there is a 15-30% chance that her child will contract HIV, which is between about one chance in six and one chance in three. If she also breastfeeds, the risk of transmission increases to 20-45%, which is between one chance in five and almost once chance in two.
However, if an HIV positive woman follows her doctor’s instructions, it is possible to reduce the risk that the child will contract HIV.  With appropriate AIDS medications for the mother and infant, it is possible to reduce the risk of HIV transmission to 1-2%, which is one chance in fifty to one chance in one hundred.  Watch our video on “Preventing Mother-to-Child Transmission of HIV/AIDS” to learn more about how to reduce an infant’s risk of contracting HIV from an HIV positive mother.

Needle Sharing: 0.67% Each Time (1 in 150 Chance Each Time)  

Another common way HIV is transmitted is when injection drug users share needles. HIV is present in the blood of an infected person. If a person with HIV uses a needle to inject a drug, some of their blood gets in and on the needle. If another person uses that same dirty needle, the other person may contract HIV as a result. Each time a person injects or sticks themself using a needle with HIV, the risk of HIV transmission is 0.67%, or about one chance in 150. This means that if you inject yourself with a dirty needle 100 times, your risk of contracting HIV might be as high as 67%, or two chances in three.  If you inject drugs, the best way to avoid contracting HIV is to use your own needles and not share them. Please also talk to a doctor about getting into a treatment program to help you to stop using drugs.

Unprotected Receptive Anal Sex: 0.5% Each Time (1 in 200 Chance Each Time)   

Anal sex is riskier than vaginal sex because anal tissue is more likely to tear during sex than vaginal tissue.  If a person is the receptive (or “bottom”) partner in anal sex and no condom is used, their risk of contracting HIV from an infected partner is about 0.5% each time, or 1 chance in 200. This means that if you are the “bottom” in unprotected anal sex with HIV infected partners 100 times, you may have one chance in two of having contracted HIV. If you have anal sex, use a condom every time to reduce your risk of contracting HIV.

Unprotected Receptive Vaginal Sex: 0.1% Each Time (1 in 1000 Chance Each Time)    

If a man infected with HIV has unprotected vaginal sex with a woman, the woman has a 0.1% chance (1 in 1000 chance) each time of contracting HIV. Women’s genitals have a larger vulnerable surface area than men's. Overall, in vaginal sex, there is a greater risk that HIV will be transmitted to the woman than to the man.

Unprotected Insertive Anal Sex: 0.065% Each Time (1 in 1538 Chance Each Time)   

If a man has unprotected insertive anal sex, or is a “top”, with a partner who is infected with HIV, he has a 0.065% chance (1 in 1538 chance) of contracting HIV each time. As in other sexual practices, using a condom correctly every time will greatly reduce his risk of contracting HIV.

Unprotected Insertive Vaginal Sex: 0.05% Each Time (1 in 2000 Chance Each Time)   

If a man has unprotected insertive vaginal sex with a woman who is infected with HIV, he has a 0.05% chance (1 in 2000 chance) of contracting HIV each time. It’s worth repeating: using a condom correctly every time will greatly reduce your risk.

Unprotected Receptive Oral Sex on a Man: 0.01% Each Time (1 in 10,000 Chance Each Time)  
Unprotected Insertive Oral Sex on a Man: 0.005% Each Time (1 in 20,000 Chance Each Time)  

If a person performs oral sex on a man without using a condom, the person has a 0.01% chance (or a 1 in 10,000 chance) of contracting HIV each time. If a man has unprotected oral sex performed on him without a condom by an HIV positive partner, he has a 0.005% chance (or a 1 in 20,000 chance) of contracting HIV each time.

Because these risks are relatively lower than some other practices such as insertive or receptive anal sex, people sometimes think that “oral sex is safe sex.” It’s important to realize that the risk of HIV transmission in either direction via oral sex is not zero, and since there’s no cure for HIV once you’re infected, why take an unnecessary risk that could change your life forever? Also realize that there are other sexually transmitted diseases such as herpes, syphilis, and gonorrhea that can be transmitted via oral sex. So if you have oral sex, use a condom each to reduce your risk of contracting HIV or other sexually transmitted diseases.

Unprotected oral sex on a woman

It is difficult to predict the risk of HIV transmission for either partner when performing oral sex on a woman.  The United States Centers for Disease Control and Prevention has reported that the risk for HIV transmission is low compared to vaginal and anal sex.  It is important to remember that there have been documented cases of HIV transmission likely occurring from oral sex on a woman, so using protection like a dental dam is always a good idea to decrease your risk of any STDs, including HIV.

Remember, the averages won’t help you if you’re the one who becomes infected. For example, unprotected insertive oral sex on a man may carry an estimated risk of 1 chance of HIV transmission in 20,000, but if you’re the one who gets infected, HIV transmission is still 100% for you. These statistics are not encouragement to have unprotected sex. Rather, they will hopefully help people to realize that all of the sexual practices we’ve listed carry some risk of HIV transmission, so it’s vital if you’re sexually active to always practice safer sex techniques such as using condoms. 

No matter who you are, you are a valuable individual, and your life matters as do the lives of those in your community. Take care of yourself and those around you. Make healthy choices that eliminate or reduce your risk of contracting or transmitting HIV. This is Dr. Becky Kuhn.

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This script was written by Eric Krock and Becky Kuhn, M.D.

This script was reviewed for accuracy and approved by Becky Kuhn, M.D. on July 30, 2011.