As restrictions and human testing have waned, new research is tackling the challenge of how we can monitor, predict, and prevent COVID-19 outbreaks, especially among vulnerable groups like hospitalised patients.
One approach is environmental surveillance. The most well-known incarnation is wastewater surveillance, which rose in prominence following the advent of the COVID-19 pandemic.
However, Coronavirus in the Urban Built Environment (CUBE) researchers are exploring an alternative method by swabbing the floors in hospitals.
How floor swabbing could control COVID-19 outbreaks
In a recent study at two hospitals in Ontario, CUBE researchers swabbed the floors of healthcare worker areas, such as change rooms, meeting rooms and staff washrooms.
They observed a strong association between the amount of SARS-CoV-2 viral matter found on the floor and the number of COVID-19 outbreaks in the hospital.
“The association between floor swabs and human cases and outbreaks was something we had previously observed in long-term care homes, and we wanted to test the hypothesis in the hospital setting,” said Dr Caroline Nott, Assistant Professor at the University of Ottawa Department of Medicine and a principal investigator of CUBE.
For every 10-fold increase in the amount of virus detected on the floor, the researchers observed a corresponding 15-fold increase in patient cases and 22-fold higher odds of COVID-19 outbreaks.
These results add to the mounting evidence that floor swabbing may provide additional monitoring to help inform infection prevention and control measures in hospitals and other settings.
Nott explained: “To be clear, COVID-19 is not spreading via the floor. It is extremely rare to catch COVID-19 from any surface.
“Rather, what we see in our floor swabs is a reflection of the burden of infection in the humans occupying the environment where we are swabbing.
“So if we start seeing an increase in the amount of virus we find on the floor, it could signal that additional COVID-19 outbreaks are on the way.”
Developing early-warning preventative measures
But why would the number of viruses on the floor in healthcare workers’ areas reflect the burden of COVID-19 outbreaks on the hospital’s patient population?
Dr Michael Fralick, Clinician Scientist at Sinai Health, Associate Professor at the University of Toronto, and CUBE principal investigator, explained: “COVID-19 is a respiratory illness. It spreads via droplets and aerosols, which can travel a relatively long distance before falling to the floor.
“We focused on healthcare worker areas mainly for pragmatic reasons: those areas are more straightforward to access and do not disrupt direct patient care, which are important considerations if an approach like this were to be implemented.”
The study was conducted over 39 weeks between July 2022 and March 2023, with a total of 760 floor swabs collected. Swabs were processed for SARS-CoV-2 using a quantitative reverse-transcriptase polymerase chain reaction.
Ensuring we’re prepared for future variants
While COVID-19 has fallen out of the public consciousness, it is paramount to build the capacity in our healthcare systems to prevent illness and death in the event of seasonal resurgence and future variants.
“We weren’t prepared for mass COVID-19 outbreaks, and as a result, many people died or have suffered long-term effects, especially vulnerable people like those being treated in hospitals or living in long-term care,” said Nott.
“We are driven to develop methods to prevent similar suffering in future, whether it is a new COVID-19 variant or a different pathogen altogether.”
