Higher COVID levels in wastewater could signal start of ‘spring wave’: Scientist
Posted March 24, 2022 11:27 am.
Last Updated March 24, 2022 5:20 pm.
Infectious diseases physician and scientist, Dr. Isaac Bogoch, expressed concerns on Thursday that Ontario is at the “beginning of a spring wave” of COVID-19 that could soon result in an increase in hospitalizations.
Bogoch noted that wastewater in many parts of the province is showing increased COVID levels, adding in a tweet that “it would not be surprising to see a bump in hospitalizations soon.”
According to analysis of wastewater from 101 treatment plants across the province, COVID activity is on the rise.
The Ontario Science Table notes that samples are typically taken three times per week at each location and there is a five to seven day lag “between the detection of SARS-CoV-2 gene copies in the wastewater, and the diagnosis and reporting of COVID-19 cases.”
It appears we are at the very beginning of a spring COVID wave in Ontario. Wastewater signals from many parts of the province are up.
It is currently unclear how large this wave (or wavelet?) will be, but it would not be surprising to see a bump in hospitalizations soon. pic.twitter.com/75VaCYO1Za
— Isaac Bogoch (@BogochIsaac) March 24, 2022
Toronto Public Health says wastewater testing allows for a more accurate picture of viral activity “regardless of the testing strategy that is in place.”
“It is particularly useful when access to PCR testing is limited, and captures people both with and without symptoms,” TPH said on its website.
“While it cannot be used to determine the number of cases of COVID-19 in the community, it identifies whether overall virus activity is increasing or decreasing.”
Dr. Vinita Dubey, Association Medical Officer of Health for Toronto Public Health, confirmed that wastewater samples have seen a recent increase, but stopped short of saying we’re entering a new wave.
“How do you define a wave? Whether it’s going to be a large wave or a blip? As we are learning to live with COVID you can expect case rates to increase and decrease.”
“This is not unexpected as we’ve lifted restrictions and as COVID-19 continues to circulate in the community,” she said.
Source: Ontario Science Table
Wastewater analysis is being touted by experts as a way to keep tabs on COVID fluctuations as governments increasingly step away from large scale testing.
RELATED: Flushing out COVID: wastewater signals can be useful tool as testing declines
“Right now we’ve got this problem where we’ve hit the limit for getting tested,” Mark Servos, a University of Waterloo researcher told the Canadian Press.
“But wastewater doesn’t care whether there’s clinical testing occurring or whether people are symptomatic or asymptomatic.”
Ontario reports 10 new deaths, ICU numbers fall
Ontario reported 10 new COVID-related deaths on Thursday as ICU numbers declined.
Three of the newly reported deaths occurred over a month ago and were added to Thursday’s total as part of a data clean up, the Ministry of Health said.
There are now 165 people in ICU due to COVID-related illness, down from 174 the previous day. During the same period, hospitalizations saw an uptick jumping from 611 to 661.
The province is reporting 2,561 new cases of COVID-19 — a number experts say is vastly underreported due to changes in testing.
The province’s chief medical officer of health, Dr. Kieran Moore, has said the actual number is estimated to be 10 times higher than the daily log, putting Thursday’s case count around 25,000.
With files from The Canadian Press
