New Brunswick has expanded COVID-19 wastewater monitoring to Fredericton and plans to launch surveillance sites in Saint John and Bathurst "in the near future," the Department of Health has confirmed.
Wastewater results can serve as an early warning of community infection levels for decision-makers and residents.
People who are infected shed the virus in their feces in the form of a genetic material called ribonucleic acid, or RNA, which can be found in raw sewage, typically five to seven days before they develop symptoms.
Sample collection began in Fredericton at the end of December, said department spokesperson Adam Bowie.
"We don't have an exact date [for Saint John and Bathurst] yet, but it's soon," he said in an emailed statement.
Results for the three communities will be posted on the Public Health Agency of Canada's COVID-19 wastewater surveillance dashboard once at least three weeks of data has been collected, said Bowie.
'Crucial tool' only used publicly in Moncton
Moncton is currently the only New Brunswick location listed. It was added to the national site in October, with data dating back to June. At the time it was announced, the department described wastewater surveillance as a "crucial tool for public health authorities."
"Public Health reviews the data, along with many other sources of information, such as confirmed case numbers and [rapid test] results, as part of its monitoring activities within the province," Bowie said Thursday.
The main benefit of wastewater surveillance to date, he said, has been "to identify COVID-19 trends earlier and more effectively."
"Early detection has the potential to impact disease transmission through enhanced public health monitoring and informed communication with the public regarding COVID-19 cases and the potential risk of increased transmission," Bowie said.
"Furthermore, unlike clinical and point-of-care [rapid] testing, wastewater surveillance provides the opportunity to monitor COVID-19 activity independent of clinical test availability, testing eligibility, or the population level testing and reporting compliance."
Bowie did not say what, if any, specific actions the department has taken in response to the Moncton levels.
He did note it's also a public tool, "offering all New Brunswickers information about COVID-19 activity in the Moncton area, and soon in other communities.
"Combined with the weekly COVIDWatch reports, it's a way to measure activity levels in the province, and to stay informed about the current situation," he said.
With more information about the prevalence of COVID in their community, people can better "assess their risk and take the appropriate steps," Health Minister Bruce Fitch has said.
Spike and drop in December
The latest available results show the seven-day rolling average of COVID-19 viral load — expressed as the number of viral gene copies found in a millilitre of raw sewage — was 29, as of Dec. 29.
That's up from 24 copies/ml, as of Dec. 22, but down from an all-time recorded high of 132 copies/ml, as of Dec. 1.
By comparison, readings in Charlottetown rose above 300 copies/ml in July and Halifax exceeded 500 copies/ml in August.
The highest readings in Canada so far, according to the dashboard, were on Lulu Island in Vancouver in June, at more than 1,100 copies/ml.
Moncton's readings varied widely throughout December, the website shows.
"As you know, we've been seeing COVID-19 activity in the province in recent weeks. It's not surprising that we'd also see fluctuations in the wastewater testing data," Bowie said.
Of those, 283 — about 28 per cent — were in the Moncton region, Zone 1.
This week's COVIDWatch report showed 521 new PCR-confirmed cases across the province between Jan. 1 and Jan. 7.
Of those, 131 — about 25 per cent — were in the Moncton region.
Data review requires 'sophistication'
COVID wastewater reading fluctuations can happen for a number of reasons, according to Pat Whalen, CEO of LuminUltra Technologies Ltd., a Fredericton-based biological diagnostic testing company.
LuminUltra isn't involved in the Moncton sampling, but does conduct wastewater testing, including a pilot project announced earlier this week with the Greater Toronto Airports Authority to test for the presence of COVID-19 Omicron subvariants and monkeypox in effluent from planes and airport terminals.
COVID readings can go up or down "first and foremost," based on the number of infected people in a community, "which can change during the holiday period, when you have people coming in from different places, or people going out," or big events, such as the World Junior Hockey Championship, hosted by Moncton Dec. 26 to Jan. 5, said Whalen.
The weather can also play a role, he said. Rain, for example, could dilute sewage and cause levels to decrease.
"These are things that highlight why this is still a pretty advanced technology and it still requires a certain amount of sophistication to be able to look at those results and understand the different variables that can impact them," said Whalen.
"The more measurements you do, generally speaking, the more precise your numbers are going to get," he added.
Natoaganeg First Nation results not public
COVID wastewater surveillance has also been underway in Natoaganeg First Nation since last fall, Bowie confirmed, but the results are not being posted on the national dashboard.
"Data from that project is collected in the community and shared with both Natoaganeg and with the Department of Health. The results from this site will not be reported publicly, but used internally by the community," he said.
"While the data belongs to Natoaganeg, the project still provides valuable information for Public Health and for community leaders around the spread of COVID-19 within the area."
Bowie could not immediately say how much the existing testing sites cost to implement or operate, or how much the new ones will cost.
The costs differ by municipality, he said.
"Given that communities already sample wastewater regularly, the additional cost for COVID-19 wastewater surveillance depends on each facility's capacity."
As part of the wastewater surveillance network, however, each community is eligible to receive funding through the safe restart agreement, which will equip them with the necessary technology and supports required for the initial set-up, he said.
"Starting next fiscal year, the Department of Health will continue to support activities by covering shipping costs and analyzing samples received by each community, free of charge," he added.
Samples are currently being tested at the Dr. Georges-L.-Dumont University Hospital Centre laboratory in Moncton and are also being sent to the national microbiology laboratory in Winnipeg for "validation" and sequencing, the department has said.