Skip directly to site content Skip directly to page options Skip directly to A-Z link Skip directly to A-Z link Skip directly to A-Z link
Volume 29, Number 8—August 2023
Research

Omicron COVID-19 Case Estimates Based on Previous SARS-CoV-2 Wastewater Load, Regional Municipality of Peel, Ontario, Canada

Lydia Cheng1, Hadi A. Dhiyebi1, Monali VariaComments to Author , Kyle Atanas, Nivetha Srikanthan, Samina Hayat, Heather Ikert, Meghan Fuzzen, Carly Sing-Judge, Yash Badlani, Eli Zeeb, Leslie M. Bragg, Robert Delatolla, John P. Giesy, Elaine Gilliland, and Mark R. Servos
Author affiliations: Regional Municipality of Peel, Mississauga, Ontario, Canada (L. Cheng, M. Varia, K. Atanas, E. Gilliland); University of Waterloo, Waterloo, Ontario, Canada (H.A. Dhiyebi, N. Srikanthan, S. Hayat, H. Ikert, M. Fuzzen, C. Sing-Judge, Y. Badlani, E. Zeeb, L.M. Bragg, M.R. Servos); University of Ottawa, Ottawa, Ontario, Canada (R. Delatolla); University of Saskatchewan, Saskatoon, Saskatchewan, Canada (J.P. Giesy); Baylor University, Waco, Texas, USA (J.P. Giesy)

Main Article

Table 1

Summary of wastewater and COVID-19 clinical data, by wastewater treatment plant and epidemic wave, Regional Municipality of Peel, Ontario, Canada, August 30, 2020–June 18, 2022*

Characteristic
 Epidemic wave
2, 2020 Aug 30–2021 Feb 20
 3, 2021 Feb 21–2021 Jul 17
 4, 2021 Jul 18–2021 Nov 27
 5, 2021 Nov 28–2022 Mar 12
 6, 2022 Mar 13–2022 Jun 18
Predominant COVID-19 variant Original Alpha Delta Omicron BA.1 Omicron BA.2
No. wastewater sample days
Clarkson WWTP 89 94 53 56 67
G.E. Booth WWTP
 89
 95
 50
 55
 67
Median daily load of SARS-CoV-2 in wastewater, N-gene copies × 1012 (range)
Clarkson WWTP 5.2 (0.5–23.8) 4.4 (<0.01–22.8) 1.0 (0.1–4.3) 10.6 (1.1–299.0) 22.8 (6.0–128.5)
G.E. Booth WWTP
 10.1 (1.4–37.3)
 9.8 (0.02−48.9)
 2.6 (0.3−15.0)
 24.1 (1.9–537.6)
 42.1 (9.6–186.5)
Median PMMoV-normalized daily load of SARS-CoV-2 in wastewater, N-gene copies × 102 (range)
Clarkson WWTP 4.6 (0.3–20.4) 5.4 (0.01–39.9) 1.7 (0.2–13.4) 20.4 (3.9–357.3) 39.4 (8.1–173.9)
G.E. Booth WWTP
 7.9 (1.1–44.4)
 10.4 (0.1–83.9)
 4.6 (0.5–43.3)
 41.8 (1.3–793.6)
 60.1 (14.7–389.6)
No. (%) wastewater samples with concentrations below limit of quantification†
Clarkson WWTP 1 (1.1) 17 (18.1)‡ 19 (35.8) 0 (0.0) 0 (0.0)
G.E. Booth WWTP
 1 (1.1)
 14 (14.7)§
 18 (36.0)
 0 (0.0)
 0 (0.0)
Median daily no. of reported COVID-19 cases (range)
Clarkson WWTP 109 (13–246) 100 (2–365) 24 (5–44) 83 (19–1,518) 45 (12–101)
G.E. Booth WWTP
 189 (17–421)
 165 (4–579)
 31 (8–69)
 136 (26–1,877)
 64 (21–150)
Median daily no. acute care admissions of COVID-19 patients at Peel hospitals (range)
 5 (0–19)
 6 (0–28)
 2 (0–10)
 12 (0–63)
 12 (3–30)
Mean weekly no. clinical SARS-CoV-2 PCR tests in Peel
 21,237
 21,050
 14,125
 18,696
 8,513
Clinical PCR tests positive for SARS-CoV-2 in Peel, % 8.3 10.2 2.7 16.7 9.0

*WWTP, wastewater treatment plant. †Limit of quantification: 3.5 SARS-CoV-2 N-gene copies per mL. ‡1 sample had N-gene concentration below the limit of detection (0.5 copies/mL). §2 samples had N-gene concentration below the limit of detection (0.5 copies/mL).

Main Article

1These first authors contributed equally to this article.

Page created: June 22, 2023
Page updated: July 19, 2023
Page reviewed: July 19, 2023
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.
file_external