Quebec scientists say monitoring traces of COVID-19 in wastewater can help detect and interpret virus levels in the population.

In a document released Wednesday, the Institut national de santé publique du Québec (INSPQ) states wastewater monitoring appears to be a more useful surveillance tool to provide early warning signs of a potential rapid increase in cases, particularly when PCR screening is limited.

However, the INSPQ notes this practice is in its infancy and more studies and experiments are needed.

The institute's document focuses on literature produced from November 2019 to February 2021 and does not address new COVID-19 variants that have emerged since then.

Since the beginning of the COVID-19 pandemic, researchers in several parts of Canada have been monitoring the contents of wastewater to observe the presence of minute traces of the virus and track its progress.

Dr. Christopher Mody, an infectious disease specialist at the University of Calgary, recently reported that PCR diagnoses account for only one-sixth to one-eighth of the actual number of cases.

He notes this gap may grow as people rely more on rapid tests.

Mody says wastewater testing can help fill some of those data gaps, calling it an extremely useful tool for assessing the extent of the disease burden.

In Quebec, a six-month pilot project to study wastewater, funded by the Fonds de recherche du Québec, the Molson Foundation and the Trottier Family Foundation, ended early last month as there was no more funding to continue, according to Polytechnique Montréal professor Sarah Dorner.

She says that before the project expired, her team observed a rapid increase in SARS-CoV-2 in Montreal's wastewater.

- This report by The Canadian Press was first published in French on Jan. 13, 2022.