Study looks at transmission of COVID-19 in public washrooms, suggests simple ways to minimize risk

Public washrooms are flush with germs, but effective handwashing, surface cleaning and maintenance are likely to minimize the risk of transmitting infectious diseases, including COVID-19, according to researchers.

A review of different studies from around the world, published in Science of the Total Environment, highlighted the dangers of open toilet lids, uncovered garbage bins and defective plumbing in spreading infections.

While there's widespread evidence contaminated surfaces can cause of fecal-oral transmission, according to researchers, no instances of airborne-related transmission of infectious diseases, including COVID-19, have been recorded in public washrooms.

The study, which analyzed evidence from restaurants, workplaces, commercial environments, post-secondary institutions, health-care settings and laboratories, comes as some borders around the world have begun to re-open amid the pandemic, which could mean more international travel and increased use of public facilities.

"Some people have been worried about using public washrooms during the pandemic, but if you minimize your time in the bathroom, wash and dry your hands properly, and don't use your mobile phone, eat or drink, then the risks should be low, especially if the bathroom is well maintained," Erica Donner, study co-author and University of South Australia environmental scientist, said in a news release.

Another thing to avoid is open-lid toilet flushing. The review found flushing could spread particles as far away as 1.5 metres and remain in the air for more than 30 minutes.

Jet-air dryers were another concern, potentially spreading droplets as far away as three metres. Uncovered garbage bins placed underneath these types of dyers could further increase the spread of pathogens by blowing trash around and by increasing the amount of aerosols in the area.

In addition, there was evidence defective plumbing could contribute to aerosols spreading through a multi-storey building.

A wide range of bacteria and viruses were identified in public washrooms, according to the study, but certain measures taken by both the public and custodians can result in a low chance of transmission.

"There is no doubt that thorough hand washing and effective hand drying is critical in stopping the spread of diseases," Donner said. "As borders open up and cases increase, people can protect themselves against COVID-19 infection by continuing to practice good hygiene. This includes handwashing and sanitizing, disinfecting door handles, toilet lids and other frequently touched surfaces.

"These habits will not only lower the risk of COVID-19 infection but also limit the risk of bacterial infections."