If your gut tells you that public toilets are awash with germs you'd be right - but it's not COVID-19 you're likely to catch and there are simple ways to reduce the risk of contracting a range of infections.
Anecdotal evidence suggests people have been avoiding public bathrooms in the past 18 months due to the perceived risk of catching COVID-19.
A new study has found people should be more concerned about other bacterial and respiratory viruses being spread through open toilet lids, uncovered bins and defective plumbing.
Researchers from the ANU and University of South Australia analysed 38 studies from 13 countries that investigated the risk of infectious disease transmission in public toilets.
Aside from considering the risks of COVID-19 transmission in bathrooms, the review also analysed other infectious disease risks from toilets in restaurants, workplaces, commercial premises and universities.
It found open-lid toilet flushing, ineffective hand washing or hand drying, poor surface cleaning, blocked drains and uncovered rubbish bins all contributed to heavy bacterial and viral loads in washrooms.
There was widespread evidence of contaminated surfaces as a cause of faecal-oral transmission but no documented instances of airborne-related infectious disease transmission.
As borders re-open, researchers are calling for more studies assessing the risk of contracting COVID-19 in public bathrooms.
The study found open bins in public bathrooms posed an infection risk, especially if they were close to electric hand dryers.
Six studies that investigated bacterial dispersal in public washrooms found jet air dryers can spread droplets as far as three metres, while toilet flushing spread particles as far as 1.5 metres and remained in the air for more than 30 minutes.
Co-author of the paper, UniSA environmental scientist Professor Erica Donner, says some people have been worried about using public toilets during the pandemic.
"But if you minimise 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," he said.
"While there is limited evidence of COVID-19 transmission via public washrooms, they are rife with bacteria, especially in those that are used frequently and not cleaned properly."
A wide range of intestinal, skin, and soil bacteria and respiratory viruses were identified in public bathrooms, posing risks of transmission.
"As borders open up and cases increase, people can protect themselves against COVID-19 infection by continuing to practice good hygiene," Prof Donner said.
Handwashing, sanitising, disinfecting door handles, toilet lids and other frequently touched surfaces was critical.
The findings have been published in Science of the Total Environment.