Can Flushing the Toilet Spread the Virus?
04 Jul 2020
Why do so many people leave the toilet seat up all the time? After all, it’s not the most attractive display object. Now, convincing medical evidence confirms we should cover the potty before flushing.
Researchers at Yangzhou University in China utilized computer modeling to show that flushing toilets does not keep all viruses and water in the bowl. They report in the journal Physics of Fluids that spray can fly as high as three feet! Ji-Xiang Wang, one of the researchers, added that the velocity of the spray could be even higher at public toilets.
Readers will understand that researching toilet seats has not been high priority for this column. But years ago, a female reader triggered curiosity about potties. She wrote, “What should I do if I’m standing in a public toilet, balancing on high heels, clutching my handbag with my teeth, panty hose at my knees, and wondering if is it safe to sit down?”
Subsequent research began with genital herpes. It’s estimated that about 18% of those between ages 19 to 49 develop genital herpes every year. There were always many myths about herpes and one was that it can only be transmitted by sexual contact.
Dr. Trudy Larsen, a researcher at the University of California, didn’t win the Nobel Prize in Medicine, but she did startle the scientific community. Larsen took samples from genital herpes lesions and placed them on toilet seats. She also asked patients with active lesions to sit on seats and then took samples. In her findings she reported the herpes virus survived for four hours on toilet seats!
Health authorities claim it would be a rare event to catch herpes from toilet seats, that the infected person would have to have open sores and the unsuspecting next user of the seat would also need a skin cut or abrasion. Perhaps you’d accept the risk if this were the only threat.
But another study at McGill University in Montreal revealed the human papillomavirus that causes genital warts could also be detected on toilet seats.
As for that spray from a flush, researchers have determined that toilets produce bioaerosols – tiny airborne concentrations of particles. Carmen McDermott at the University of Washington School of Medicine reported in the Journal of Hospital Infection that the SARS virus could live in aerosols for three hours.
Good sense dictates that toilets are not the most hygienic areas. For instance, studies have found that 97% of seats have bacteria that cause boils, 81% germs that cause diphtheria and hepatitis. Other bacteria cause sore throats and food poisoning.
What about men? Studies show that when men urinate at the urinal, the spray travels up to three feet!
This column does not intend to trigger “potty paranoia”. But this fear exists. For instance, one survey showed that 30% of people “hold it”, rather than use a public toilet. Some 40% flush the toilet with their feet and 60% hover rather than sit on the toilet.
So what’s the answer? Bryan Bzdek, an aerosol researcher at Britain’s University of Bristol says, “Keep the seat down before flushing, clean the seat, and wash your hands.”
Sadly, too many people do not wash their hands – even doctors. At one infectious disease meeting of doctors, a student monitored their behaviour in a washroom. An amazing 50 percent of physicians did not wash their hands!
Final advice. Mother was right to be cautious of public toilet seats. Now, our computer age has proved flushing can toss viruses in fecal matter into the air. So, learn to keep toilet seats down before flushing and all the time when not in use. It’s safer and even looks cleaner.
