Which Infections Can I Catch Through Oral Sex?

Oral sex is the stimulation of the genitals using the mouth and tongue. It is one of the most common routes by which sexually transmitted infections (STIs) are passed on. You can catch a sexually transmitted infection (STI) even if you have only one sexual partner. However, your risk of catching an infection increases when you have more partners.

What Is Oral Sex?

Oral sex involves using the mouth to stimulate a sexual partner's genitals or genital area. Types of oral sex include oral sex on the penis (fellatio), the vagina (cunnilingus) and the anus (anilingus).

How common is oral sex?

Oral sex is widely practised among sexually active adults. More than 85% of sexually active adults aged 18-44 reported having had oral sex with an opposite-sex partner at least once. A separate study, conducted in the USA between 2011 and 2015, reported that 41% of young people aged 15-19 had had oral sex with an opposite-sex partner.

Can Sexually Transmitted Infections (STIs) Be Passed On During Oral Sex?

Yes. Many STIs and other infections can be transmitted through oral sex. Anyone who has contact with an infected partner can catch an STI in the mouth, throat, genitals or rectum. The risk of catching an STI through oral sex or passing it on to others varies depending on the type of the specific STI, the type of sexual contact and the number of sexual encounters.

In general:

1. When you perform oral sex on a partner who has a genital or anal/rectal STI, it is possible to catch some STIs in the mouth or throat.
2. When you receive oral sex from a partner who has a mouth or throat infection, it is possible to catch certain STIs in the genital area.
3. You can have an STI in more than one site at the same time. For example, you can have an STI in the throat and in the genital area.
4. Some STIs transmitted through oral sex (for example, syphilis, gonorrhoea and intestinal infections) can spread within the body.
5. Oral sex involving the anus (or anilingus) can transmit hepatitis A and B. It can also transmit intestinal parasites such as Giardia and bacteria such as E. coli and Shigella.
6. If you have an STI, you may not be aware of it, because many STIs have no symptoms. It is possible to pass on STIs even if you have no signs or symptoms.

Which STIs Can Be Passed On Through Oral Sex?

STIs frequently transmitted through oral sex include:

1. Gonorrhoea (Gonorrhoea)
2. Genital herpes (HSV-2)
3. Syphilis (Syphilis)
4. Human papillomavirus (HPV)

Infections transmitted less frequently through oral sex include:

1. Chlamydia 
2. HIV/AIDS
3. Hepatitis A, hepatitis B and hepatitis C
4. Genital warts (HPV)

Is Oral Sex Safer Than Vaginal or Anal Sex?

It is difficult to compare the risk of catching certain STIs from specific sexual activities.

1. Most people who have oral sex also have vaginal or anal sex.
2. There are few studies examining the risks of catching STIs other than HIV. There are few studies examining the difference in the risk of acquiring STIs between oral sex on the vagina or anus and oral sex on the penis. Studies show that the risk of acquiring HIV through oral sex (giving or receiving) is much lower than the risk through anal or vaginal sex. This may not be true for other STIs.
3. In one study of gay men with syphilis, 1 in 5 reported that they had only had oral sex.
4. The risk of getting HIV through oral sex may be very low, but it is difficult to know the exact risk. If you have oral sex, you should protect yourself. Catching certain STIs in the throat may be no less harmful than catching them in the genital area or rectum. Having these infections is thought to increase the risk of catching HIV in the throat. In addition:
5. Chlamydia or gonorrhoea infections in the throat can make it easier to pass these infections on to other people through oral sex. This is especially important for gonorrhoea, because throat infections can be harder to treat.
6. Infections caused by certain STIs spread within the body, so infections acquired in the throat can lead to the same health problems as infections acquired in the genital area or rectum.
7. Infections caused by certain HPV types can progress to mouth or neck cancer.

What Factors May Increase the Risk of Catching or Acquiring an STI Through Oral Sex?

A person may have some factors that can increase the risk of acquiring HIV or other STIs during oral sex with an infected partner. These factors are as follows:

1. Poor oral health, which may include tooth decay, gum disease or bleeding gums, and oral cancer.
2. Sores in the mouth or genital area.
3. Exposure to "pre-cum" or "semen" (also known as pre-ejaculate or ejaculate). However, there are no scientific studies showing whether these factors increase the risk of acquiring HIV or STIs through oral sex.

How Can You Prevent STI Transmission During Oral Sex?

You can reduce the risk of getting or passing on STIs during oral sex. Always use a condom, a dental dam or other barrier methods during oral sex.

1. For oral sex on the penis: a. Cover the penis with a non-lubricated latex condom. b. If you or your partner is allergic to latex, use plastic (polyurethane) condoms.
2. For oral sex on the vagina or anus: a. Use a dental dam. b. Cut a condom open to make a square and place it between your mouth and your partner's vagina or anus. The only way to prevent STIs is not to have vaginal, anal or oral sex.

If you are sexually active, you can reduce your risk of getting an STD by:

1. Being in a long-term, mutually monogamous relationship with a partner who does not have an STD (for example, who has negative STD test results).
2. Using latex condoms correctly every time you have sex.

It is important to remember that many people who have STIs may not be aware of their infections. STIs often have no symptoms and go unnoticed. If you have had oral/anal sex, a throat/rectal swab (PCR) is needed; for throat gonorrhea, a test of cure is performed after 7-14 days. Please contact our laboratory to have an STI test.