The Hazards of Bathroom Seats - Medical Myths - Harvard Commentaries

Sometimes it seems that the number of ways you can get into trouble doing everyday activities is exceeded only by the number of recommendations about how to avoid such trouble. For instance, I recently heard it suggested that you could contract all sorts of unpleasant and even dangerous diseases by sitting on a dirty public restroom seat. Examples include gonorrhea, syphilis, HIV, other sexually transmitted diseases, hepatitis and even pregnancy!

Although any contaminated surface has the potential to transmit an infectious agent to people who come into contact with it, the real risk of developing illness from a toilet seat is nearly zero. The risk almost surely does not warrant the enormous efforts many people make to avoid contact with public toilets.

One recent poll reported that the majority of the U.S. population never make contact with a public toilet seat, reflecting a remarkable amount of fear. Such fear may reflect concern about the risk of acquiring an illness, misunderstanding about how such illnesses are contracted and a high degree of suspicion about the people who previously used the toilet.

Many infections can be transmitted by contact. A good example is the common cold — the best ways to avoid giving a cold to someone else are to wash your hands frequently and to avoid close contact. Of course, these methods are not foolproof, because some respiratory viruses may be transmitted through the air rather than through touch. As for other infections of concern, illness can spread in a number of ways (especially through sexual contact), but rarely, if ever, through contact with a toilet seat. Here are just a few examples:

Gonorrhea is generally transmitted through direct sexual contact; an infected woman may infect her newborn during delivery.
Syphilis is most commonly transmitted through direct sexual contact, but an infected mother can infect her fetus.
HIV may be transmitted through transfusion of infected blood products or through a needle stick from a contaminated needle (for instance, as accidentally occurs among health care workers or as occurs among intravenous drug users). In addition, HIV may be spread through sexual contact. A mother may infect her child before birth or during breast feeding. Rarer modes of transmission include the use of infected semen for artificial insemination and transplantation of an organ from an HIV-infected donor.
Chlamydia is usually transmitted through direct sexual contact, or it can be spread from an infected mother to her newborn.
Viral hepatitis may be spread in a number of ways; it depends on the type of virus. Transmission may occur through the consumption of contaminated food or water, sexual contact, fetal development in an infected mother, injury with a contaminated needle or surgical instrument or transfusion with contaminated blood products. Nonsexual but close contact with an infected person may lead to infection, but this generally occurs through activities such as sharing a toothbrush or a drinking glass or through direct contact with an open sore.

The chances of getting pregnant by sitting on a toilet seat are essentially zero. Could it happen? Perhaps with great effort, but when a toilet seat is used in the usual way, there is no significant risk of becoming pregnant.

If you find yourself in the unpleasant situation of having to use what is clearly an unclean toilet, you may choose to avoid direct contact and, if available, use a covering on the seat. Recognize, however, that although the hygiene of those who preceded you may be disappointing, you have little to fear.

Robert H. Shmerling, M.D. is associate physician at Beth Israel Deaconess Medical Center and associate professor at Harvard Medical School. He has been a practicing rheumatologist for over 20 years at Beth Israel Deaconess Medical Center. He is an active teacher in the Internal Medicine Residency Program, serving as the Robinson Firm Chief. He is also a teacher in the Rheumatology Fellowship Program.