Hand washing and sanitizing not enough
University of South Australia
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| Credit: Harpic |
A
global review of the risks of bacterial and viral transmission in public
bathrooms has found that bioaerosols can potentially be transmitted throughout
a multi-story building by defective plumbing and that leaving toilet lids open
after flushing can disperse contaminated droplets beyond a meter.
Uncovered
rubbish bins in public bathrooms are also flagged as a risk, especially if
located under or close to electric hand dryers.
Researchers from the ANU and University of South Australia assessed 38 different studies from 13 countries that investigated the risk of infectious disease transmission in public washrooms. Their findings have been published in Science of the Total Environment.
Aside
from considering the risks of COVID-19 transmission in bathrooms, the review
also analyzed other infectious disease risks from public toilets in restaurants,
workplaces, commercial premises and universities.
The
results showed widespread evidence of contaminated surfaces as a cause of
fecal-oral transmission, but no documented instances of airborne-related
infectious disease transmission.
In
the wake of borders re-opening, researchers called for more studies assessing
SARS-CoV-2 transmission risks in public washrooms.
Co-author
of the paper, UniSA environmental scientist Professor Erica Donner, says
anecdotal evidence suggests that public washrooms have been avoided by users in
the past 18 months due to perceived risks of COVID-19 transmission.
"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," Prof Donner says.
"While
there is limited evidence of COVID-19 transmission via public washrooms, they
are rife with bacteria, especially 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 washrooms, posing risks of transmission.
Open-lid
toilet flushing, ineffective hand washing or hand drying, poor surface
cleaning, blocked drains and uncovered rubbish bins all contribute to heavy
bacterial and viral loads in washrooms.
Six
studies investigated bacterial dispersal in public washrooms, showing jet air
dryers can potentially spread droplets as far as three meters, and toilet
flushing spreading particles as far as 1.5 meters and remaining in the air for
more than 30 minutes.
One
2021 study estimated that the number of particles from a toilet flush was
equivalent to droplets from a person talking loudly for just over six and a
half minutes.
"Although
there is a potential risk of aerosols spreading from toilet flushing and hand drying,
we found no evidence of airborne transmission of intestinal or respiratory
pathogens in public bathrooms in the literature we reviewed," Prof Donner
says.
"However,
there is no doubt that thorough hand washing and effective hand drying is
critical in stopping the spread of diseases.
"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."