Q&A: Are the HIV Risks of Oral Sex Lower?

Q: Is it true that oral sex carries the lowest risks of HIV infection, as opposed to vaginal and/or anal sex? If so, why is this?

 A: Yes, oral sex does appear to have a lower risk than vaginal or anal sex. I say “appear” because the only way to fully understand the risk is to study people who only have oral sex and not anything else. Such people would be very hard to find. But we can say pretty confidently that the risk is lower, although not totally absent.

Why you ask?

A couple of factors come into play. First, the oral cavity is not the easiest barrier for bacteria, viruses and other “germs” to cross into the blood stream. This makes total sense because our mouths come in contact with all sorts of things in the environment that we should be protected against. Also, the acidic environment of the stomach is a hostile environment for germs as well. The immune system is also reinforced in this area to attack any germs that breach the barrier. This is an important function of the tonsils (although HIV is tricky and can act as a “Trojan horse” to cause infection).

To strengthen this defense, the lining of the oral cavity, including saliva, contains a variety of compounds that can block HIV infection. Special infection fighting compounds called defensins and mucins can actually trap HIV and keep it from infecting cells. A good colleague of mine, Dr. Habtom Habte, did some very important studies on mucins’s defense against HIV while he was working in South Africa. Other compounds known as CC-chemokines have been shown to protect individuals from infection who have been exposed to HIV through oral contact. So it’s safe to say that the risk is low.

But low doesn’t equal zero!

If either partner has cuts, abrasions or sores on their genitals or in their mouth, this could increase the risk of transmission, particularly if they are bleeding. You should also be concerned that other STD’s can be transmitted by oral sex, such as gonorrhea and syphilis, and both the person performing oral sex as well as the recipient can be infected. For HIV transmission, the person performing either fellatio or cunnilingus is at slightly increased risk of infection than the recipient is. To be perfectly safe, a condom should be used for oral-penile contact. For oral-vaginal contact, a dental dam should be used.  This is a thin sheet of latex used by dentists for certain procedures.

Q&A: Is It True That Men Can’t Get HIV Infections From Women?

Q: I think I actually witnessed the spread of HIV misconceptions! Basically, I overheard a bunch of male coworkers talking about married male celebrities and their infidelities, and how the wives of these celebrities had nothing to worry about regarding the rumored lack of protection used during these indiscretions, because “it’s next to impossible for a man to pick up the HIV virus from a woman.” Yes, I know, this is nonsense, but just for the record…is there any data to support that one group of people can more easily spread the virus than another group? Also, where in the world did such a potentially dangerous misconception come from?

A: Well, I can top that misconception with one even more ridiculous. There are some parts of Africa where it is widely believed that a man infected with HIV can rid himself of the infection by having sex with a virgin! This deplorably ignorant myth has led to widespread rape of young girls, and of course, new infections. Ignorance kills!

Your co-workers are obviously incorrect.  It is true that it is easier for an HIV-infected man to infect a woman than it is for an HIV-infected woman to infect a man.  This is a result of the basic anatomy of sexual intercourse. However, this is a far cry from thinking it is virtually impossible for a man to pick up HIV from a woman. In the early years of the AIDS epidemic in the US, it became well recognized that gay men and intravenous drug users were the major groups affected by HIV. It appears that some heterosexual men assumed that if they weren’t having sex with men, or injecting drugs, they were not at risk for HIV infection.

This erroneous belief has contributed to the devastating epidemic among African-Americans. While we were painting a picture of HIV as a “white gay” disease, we should have been looking across the Atlantic. In Africa, where several million of people have already died, homosexual sex and intravenous drug use represent only a small percentage of the risk factors for those who are and were infected. Yet, there are, and have always been, almost equal numbers of men and women infected with the virus! This should have tipped us off of the risk from heterosexual intercourse decades ago. It did not.

In my city of Washington DC, the number of new infections from heterosexual intercourse surpassed those from homosexual intercourse and intravenous drug use a few years ago.

Factors That Can Increase HIV Transmission

Research on heterosexual transmission has shed some light on the factors that can increase transmission:

• Years ago, studies from Africa demonstrated that the amount of virus in a person’s blood is a major determinant of whether a person’s partner gets infected, whether they are male or female. In general, women need more virus in the blood to infect a man than a man needs to infect a woman. However, if we reduce the amount of virus in the blood to undetectable levels (through treatment with medications), almost no transmission occurs!

• Uncircumcised men are at increased risk of being infected by women. This has resulted in massive campaigns in many African countries to get men circumcised in communities where it is not commonly practiced.

• In addition to this, the presence of an STD (e.g. gonorrhea, herpes, Chlamydia, syphilis) can increase infection by a couple of ways. First, the infection increases the production of HIV in semen or vaginal fluid, so the partner is exposed to more virus.  Second, the infection damages the mucous membranes making it easier for HIV cross. Women may often have no symptoms of an STD and may not seek care in a timely manner.

What’s one factor that can help decrease HIV transmission? Sharing knowledge and helping to dispel these dangerous myths. Tell your coworkers the facts – it may help save lives!