Airports are a hotspot for the entry and spread of new SARS-CoV-2 variants (and other pathogens), and testing the wastewater from airports and planes is proving to be a useful surveillance tool.
A group of Canadian researchers at the forefront of improving wastewater surveillance in planes and airports are also investigating the addition of surface testing (swabbing) in airports and on airplane surfaces.
“Wastewater’s fascinating. It’s one of the most important surveillance tools arising out of the pandemic globally,” Dr. Doug Manuel said in a recent interview. “It’s moving so fast, and we have more and more of what we call use cases or examples of where it can fit.”
Manuel is a senior scientist with the Ottawa Health Research Institute and a professor at the University of Ottawa. He’s also director of the Wastewater Surveillance Research Group (WWSRG) with CoVaRR-Net (Coronavirus Variants Rapid Response Network).
Members of Manuel’s research group developed a model that standardizes the data collection, reporting, and storage of wastewater, making it easier for users to share and compare data.
Their model has been adopted by 27 countries and is being recommended by the European Union.
“It’s not used everywhere, but it’s becoming more widespread. And it’s becoming more of the standard internationally. At least everyone is aware of it,” Manuel said.
“It’s so comprehensive, the crosswalk between different data systems. At the beginning of the pandemic, people were just trying to collect the data so fast and they set up their own Excel sheets or databases. Some of those are still continuing, but now they have a roadmap to be able to harmonize.”
Amount of airport wastewater testing increasing ‘dramatically’
A spokesperson for Halifax Stanfield International Airport said there’s currently no wastewater testing happening at that airport.
But there is wastewater testing taking place at several Canadian airports.
“In general, over the last month or so, the amount of wastewater testing in airports and airplanes is increasing dramatically,” Manuel said.
The Public Health Agency of Canada (PHAC) has short-term wastewater testing programs in place at a select number of airports.
In an email, PHAC spokesperson Anna Maddison said they’ve implemented a short-term aircraft wastewater testing program for flights coming directly from China and Hong Kong to Toronto’s Pearson Airport and to Vancouver International Airport.
“These projects complement a current pilot at Pearson which focuses on sampling from terminals and the lavatory depot, where all airplane waste is dumped. The wastewater samples are ultimately sequenced to detect new variants and monitored to detect trends in circulating variants,” Maddison wrote.
“PHAC scientists are also planning to compare the wastewater data from airplanes and airports to data obtained from national sampling and testing. This will help scientists determine the most appropriate types of testing needed to support public health decision-making.”
Continuing to compile wastewater surveillance data
Maddison said PHAC continues to work with other federal departments, provincial, territorial, municipal, and Indigenous governments and academics across Canada to compile wastewater data into the COVID-19 wastewater surveillance dashboard.
She said the dashboard will continue to be expanded to provide additional data to people in Canada. That will include the addition of more cities.
“Obtaining information from multiple sources (airplane, airport terminal, and domestic data) along with genomic sequencing data collected and published by international partners, will continue to support PHAC’s evidence-based decision-making as we monitor for new variants of concern and their impact,” she wrote.
World wide wastewater web
Manuel said “rapid activities” over the holidays and concerns about a new variant from China “really accelerated” discussions about the usefulness of airport/airplane wastewater testing.
“Some countries, including Canada, have concerns about the level of surveillance there (in China). So we were like, ‘If we can’t get information coming out from places like China, can we substitute that with airports and airplanes?’ People started getting interested in looking at that,” Manuel said.
“It becomes much more powerful if you think of it as what I call the world wide wastewater web. If you have airports and airplanes around the world testing, then you may have a really novel way of early identification of new variants. Especially from regions which don’t have as high a level of surveillance of COVID or new pathogens.”
Potential for ‘massive return’ on investment
The WWSRG also conducted a pilot project at the airport in Sault Ste. Marie, Ont. earlier this month to determine the potential benefits of surface testing airport floors and surfaces.
In his 30 years working in the public health realm, Manuel said it’s “very rare” to see a potential new surveillance system with such promise. It’s affordable, doesn’t require hundreds of individual PCR tests, and one round of surface sampling can cover an airport or plane.
It offers early detection of variants and multiple pathogens. The fact that it’s population-based also makes it easier to access harder-to-reach areas and to better understand what is happening in specific communities.
“It’s not this high, heavy level of testing that we need to maintain,” Manuel said.
“More population surveillance as an early warning system for new variants or new pathogens has the potential for massive return on investment.”
‘Don’t have a full sense of the COVID-19 picture anymore’
Dr. Lucas Castellani is the medical director of infection prevention and control and medical director of medicine at Sault Area Hospital.
He’s also a collaborator on CoVaRR-Net’s Coronavirus Built Environment (CUBE) project and part of the research team that recently conducted surface testing as part of the pilot project at the Sault Ste. Marie airport. That initiative involved taking multiple swabs from several areas of the airport, including departures and arrivals.
Castellani said because so few people are now testing for COVID-19, we “just don’t have a full sense of the picture anymore.” He said this kind of testing helps provide a broader sense of what’s happening in our communities.
“If you’re on an airplane, you may or may not actually go to the washrooms, but you are breathing the whole time. When you breathe, the particles come out, they fall on the floor,” Castellani said in an interview.
“So it’s complementary. What the wastewater may not pick up, you’ll pick up with surface testing, hopefully, and hopefully it’ll give you a sense of what’s happening now.”
The Sault Ste. Marie airport pilot project piggybacks on the group’s successful surface swabbing research last year in hospitals and long-term care facilities (reported here). Through sampling of floors with swabs, researchers were able to detect COVID-19 up to a week before cases were reported.
Early warning system
Castellani said the smaller size of Sault Ste. Marie’s airport and the willingness of its airport authority to participate made it the ideal place to determine the feasibility of this testing method in airports.
“We thought, why not get some of the kinks out initially. See if there are any barriers to the actual physical process of swabbing in an airport, see if we can actually reasonably isolate from the floor in an airport,” Castellani said.
“Because sometimes people are in places only for so short a period of time that it’s hard to find the viruses.”
Castellani said there are several benefits to surface testing, including the ability to quickly swab different locations and the fact that it’s so simple to carry out.
“Wastewater sampling takes a little more expertise in a sense, because you have to access that wastewater in the right way, take the right sampling, and then processing is a little bit of a complex technique,” Castellani explained.
“For surface testing, you literally swab a small paper size area of the floor, not even. Then you put the swab back into the container and you process it fairly similarly to the way you would process other types of PCR testing or molecular testing techniques.”
Although this surveillance tool isn’t yet common and the science is still in its infancy, Castellani believes it holds great promise.
“These types of surveillance tools give you a better understanding of what’s happening. Then you can implement the first steps in terms of non-pharmaceutical interventions or the public health interventions that actually work to prevent spread,” Castellani said.
“It’s actually a good tool that works not just for COVID or variants, but other viruses or emerging pathogens. It’s like an early warning system.”
Better sense of what’s happening
Castellani hopes to have preliminary data from their recent surface testing at the Sault Ste. Marie airport sometime within the next few weeks.
If that pilot is successful, they plan to expand the project to other Canadian airports. If logistics can be worked out, they’d also like to include surface testing on planes.
“What I think our goal would be is to understand true international travel at the bigger airports. Not to say that we couldn’t use this technique in other harder to reach places,” Castellani said.
“It’s just that I think we also need to get a sense of what’s happening in the bigger airports and we also have to understand the feasibility of that. And then also pursuing the airplane piece as well.”