Public washrooms in the time of COVID-19: Facility features and user behaviours can influence safety

During the COVID-19 pandemic, questions have been asked if using a public washroom poses a risk.  Washrooms can be busy spaces that remain essential for parks, campgrounds, transit hubs, sports and entertainment centres, and other public venues. Public washrooms are also necessary for under-housed populations and people who are on the road for work, such as long-haul truck drivers, construction workers, and others who may spend a large part of their day outdoors.

To date, no COVID-19 clusters have been linked to public washroom use. Studies of washrooms during COVID-19 have largely focused on hospital settings with patients. This research has detected SARS-CoV-2 particles in the air and surfaces of hospital washrooms and in and around isolation rooms.^1-4 However, environmental sampling studies for SARS-CoV-2 in public washroom settings have not yet been conducted, leaving a gap in our understanding of exposure in these spaces. As such, an overview of the factors that can influence the transmission of SARS CoV-2 virus in public facilities is warranted.

A synthesis of the peer-reviewed literature identified five factors that may modify pathogenic exposures in public washrooms: human behaviour, physical distance, amenity options, ventilation, and maintenance schedules.  These are considered in light of what is currently known about how the COVID-19 virus is transmitted between people.

COVID-19 transmission pathways and relevance to the WC setting

The SARS-CoV-2 virus is transmitted primarily through close contact with an infected person and through the inhalation of infected droplets and aerosols generated by coughing, sneezing or even talking, singing, shouting and laughing.⁵ To date, the evidence suggests that indoor spaces that promote close contact for longer periods of time are the most likely to facilitate respiratory viral transmission.

Touching surfaces that are contaminated with the virus (fomites) and then touching the face (nose, eyes, mouth) is another potential route for transmission for COVID-19,⁵ although the role fomites play in COVID-19 disease transmission remains unclear. The SARS-CoV-2 virus persists on hard surfaces such as stainless steel, glass and plastic for a long time (up to seven days), although the duration of infectiousness remains unclear.⁶ The virus is effectively eliminated from surfaces by cleaning and the use of chlorine or alcohol-based disinfectants.⁷

Specific to the washroom setting is the consideration of faecal transmission, which is another possible transmission route as the SARS-CoV-2 virus is continually shed in infected and convalescent individuals. Patients with more severe COVID-19 have higher concentrations of SARS CoV-2 in their stool and viral particles can be detected in stool long after respiratory samples test negative.⁸  However, whether the viral particles in faeces remain infectious is unclear. To date, only a limited number of case studies have isolated viable virus from patients’ faeces.^9-12

The previous SARS outbreak in 2003 documented viral coronavirus transmission via faeces in a residential complex (Amoy Gardens, Hong Kong).¹³ Aerosolized faeces is thought to have transmitted SARS to residents on floors above and across from where a patient used toilet facilities.¹³ A similar exposure scenario is being considered for a 2020 COVID-19 cluster in a Guangzhou, China high-rise.¹⁴ The relevance of residential plumbing transmission for public toilets remains unknown although this recent  investigation in China supports the continued the need for vigilance around faecal transmission via sewage.

Public washrooms- factors that may influence viral transmission risk

Human behaviors, physical distance, amenity options, ventilation and cleaning schedules are variables than can mediate pathogen exposure opportunities in public washrooms. These factors are considered in light of what is known to date about COVID-19 transmissibility.
 

Human behaviors

The amount of time spent inside a public washroom and hand hygiene practice are behaviors that influence potential respiratory exposures. Generally, most people report spending only a short period of time in public washrooms,¹⁵ although women spend significantly longer than men (in part due to fewer toilets and longer line-ups)^16,17 and older visitors spend longer in public toilets than younger visitors.¹⁸

Beyond visit time, proper hand washing has been clearly shown to reduce pathogen transmission risk. However, behavioral research pre-pandemic shows that many people, particularly men, don’t wash their hands after using the toilet.^19-22 Since COVID-19, a survey of 2,000 Britons found that more people are washing their hands than usual, but 12% still report not washing after using the toilet.²³ Drying hands completely after washing is also an important step for maintaining clean hands. Studies of hand drying have found that many people skip this step, don’t stay at hand dryers long enough or use their own clothes to dry their hands.²⁴  These behaviors reduce the effectiveness of hand washing and increase the likelihood of cross contamination when leaving public washroom.

Physical distance

Small indoor spaces with inadequate ventilation and crowding are common factors in COVID-19 clusters and outbreaks. Recent research has shown that that, overall, physical distancing efforts have been effective during the COVID-19 pandemic.  Recommendations for public spaces also apply to public washrooms.  Strategies that support physical distancing in public washrooms include closing off urinals or sinks that are side by side, as well as using signs and floor markers to keep people apart.  Some facilities with two doors have applied one-way traffic flows to help reducing crowding. 

Amenity options

Good hand hygiene helps to remove pathogens from hands and helps reduce the spread of COVID-19. Public washrooms play an important role in supporting hand hygiene for people who are on the go. Using soap and water for at least 20 seconds mechanically removes of pathogens from hands and is the preferred strategy for getting hands clean. When soap is not available, chemical removal using alcohol-base hand rubs is recommended. Using hand sanitizer safely and details on product recalls have been discussed in previous NCCEH blogs. An NCCEH poster that outlines Do’s and Don’ts for safer hand sanitizer use during the COVID-19 pandemic is also available. 

The type of amenities in public washrooms and how they are used have been studied in the context of general infection control. In general, fomite transmission opportunities are fewer when “touch-less” sensor-operated amenities such as sinks, soap and paper towel dispensers are provided ²⁵. These amenities also reduce the work burden for cleaning staff by reducing the number of high touch surfaces that need to be cleaned. Other amenities in public washrooms that have been studied for their role in pathogen transmission are electric hand dryers and toilets.

Hand Drying

The choice of hand drying method can influence hand hygiene. While warm air and jet dryers are effective,²⁶ they must be used long enough to achieve dry hands. Evidence shows that people often do spend enough time at the dryer to dry hands properly or may instead use their own clothing to dry hands,²⁴ which can lead to recontamination. Papers towels are the most effective means of getting hands drier faster and more efficiently that other methods.²⁷ Paper towels also have the added benefit of being useful for opening doors and turning off faucets in a manner that reduces cross contamination. Touchless or automatic paper towel dispenser, as well as automatic doors or doorless entry ways, are even better choices for reducing contamination during hand drying and to keep hands from re-contamination after washing.

Toilets flushing

Toilet flushing can generate droplets of faecal pathogens within plumes (known as toilet mists or aerosols) that can be inhaled or settle on surfaces around the toilet.²⁹  Epidemiologic investigations of outbreaks in cruise ships and airplanes suggests that toilet aerosols may play a role in the spread of pathogens,³⁰ particularly persistent ones such as norovirus, Clostridium difficile, and other pathogens.  A 2020 investigation of a COVID-19 outbreak on an aircraft surmised that exposure via the airplane’s toilet was the most plausible cause of transmission between passengers.³¹ To date, little research has addressed SARS-Cov-2 toilet aerosol generation, although researchers have speculated on this process and its role in COVID-19 transmission.³² The risk from toilet aerosols depends, in part, on whether SARS-CoV-2 particles remain infectious in faeces or urine. Toilet type, including the high energy flushing and the use of toilet lids, can also influence how much faecal matter is aerosolized.³⁰ However, most public washrooms do not offer toilets with lids, which when closed, have been found to reduce aerosol generation considerably.³³

Ventilation

Public washrooms in parks, recreational areas and campgrounds often rely on natural ventilation from windows, cut-outs, slats or vents. Facilities in community centres or public buildings benefit from a well-maintained, building-wide HVAC systems that operate at optimal efficiencies.  Providing adequate ventilation, checking HVAC systems to ensure that exhaust fans are working and augmenting ventilation where possible are steps that have been encouraged for all indoor spaces during the pandemic.   While some agencies recommend keeping washroom doors open, these efforts need to be tempered with issues of privacy and safety and should only be done where appropriate. For a general review of the role of ventilation in influencing COVID-19 transmission risk, see the NCCEH’s July 2020 blog

Maintenance and Cleaning

There are many high-touch surfaces such door and stall handles, locks, levers and faucets in public washrooms that require cleaning and disinfecting. The SARS-CoV-2 virus is effectively inactivated by proper cleaning and disinfecting procedures. Health Canada provides a searchable list of hard surface disinfectants approved for use during COVID-19. Many agencies recommended more frequent cleaning during the pandemic, with at least twice per day a common recommendation. Cleaning tasks should be expanded to include all high-touch surfaces (light switches, entrance and exits doors, stall handles and locks). Regularly cleaning and sanitizing washroom floors is also warranted given evidence that has linked sewage to viral particles on shoes.³⁴

The increase in cleaning procedures and frequency may impact staffing requirements. Facility operators should ensure they have enough staff to implement the recommended increases in cleaning duties.

Limitation and gaps in current evidence

There is limited research on SARS-CoV-2 exposure in washroom settings and most work to date has been conducted in hospital settings. More environmental sampling research of air and surfaces is needed to characterize exposure potential in shared public washrooms. Continued research on the quantity and infectiousness of SARS-Cov2 particles shed in faeces and urine will also help ascertain whether washrooms visits pose increased risks.³⁵  

The limited research on pathogen exposure in washrooms has been done on “typical” configurations, with little attention to accessible washrooms or family washrooms that often have more high-touch surfaces such as chairs or diaper stations.

Key Points

While there is community transmission of COVID-19 by both symptomatic and asymptomatic persons, strategies that reduce exposures to infectious droplets, aerosols and fomites are important in all public spaces. Operators of public washrooms and visitors can take steps to reduce potential exposures by considering the following:

Janitorial staff also play an important role by keeping public washrooms clean and safe for public use. Facility operators should keep staff up-to-date on the latest COVID-19 cleaning and disinfecting guidance. Workers should also review the instructions for the products they are using to ensure they are using them correctly and are taking the right precautions to keep themselves safe. Staff should be able to access the PPE that they need to work safely and there should be enough staff to meet the increased cleaning demands generated by the pandemic.

Public washrooms are important, shared places that benefit from the public health recommendations for small, indoor spaces as well as those that reduce fomite opportunities. Facility operators, cleaners and visitors all have important roles to play in keeping public washrooms safe and open during the COVID-19 pandemic. Future pandemic planning should explicitly consider public washrooms, recognize their importance to the overall health of communities and design or renovate these spaces using strategies to reduce respiratory and fomite exposures.

Acknowledgement: The author would like to thank Muhammad Qazi for his assistance researching this topic. 

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