Re Dr. Moore’s January 15th letter to Dr. Hirji
I am writing to express my support for the additional school safety mitigation measures instituted by Dr. Hirji and to register my concerns about Dr. Kieran Moore’s January 15th letter to Dr. Hirji. I am a Niagara region resident and also happen to be a statistician and analyst of covid-19 in Ontario.
Following are some of my immediate thoughts on reading Dr. Moore’s letter this morning.
Weekly classroom CO2 monitoring
There is a wealth of evidence highlighting the connection between ventilation and reduced covid transmission risk which I will not repeat here. See Professor Jimenez @jljcolorado for example. There is also clear evidence that CO2 monitors are an effective proxy tool to measure ventilation related to covid transmission risk, by measuring rebreathed air in a room. The greater the CO2 ppm readings, the greater the sharing of exhaled air including any infectious airborne particles. Rooms with prolonged, larger groups require more careful monitoring, ie school classrooms.
“Around 300,000 carbon dioxide monitors are to be made available to schools in England next term to help improve ventilation and lessen Covid outbreaks.” — BBC England, August 2021
https://www.bbc.com/news/education-58285359
“Carbon dioxide levels reflect COVID-19 risk: Research confirms value of measuring carbon dioxide to estimate infection risk” — Science Daily, April 2021
https://www.sciencedaily.com/releases/2021/04/210407143809.htm
“the real-time visualization and monitoring of CO2 concentrations allows effective air exchanges to be implemented and contributes to prevent SARS-CoV-2 transmission” - Journal of Env Res, NIH Natl Library of Medicine, July 2021
https://pubmed.ncbi.nlm.nih.gov/34224708/
“A Swiss study has found that poorly ventilated school classrooms record up to six times as many Covid-19 cases compared with those which are regularly aired.”
https://www.swissinfo.ch/eng/society/study-shows-benefit-of-regular-classroom-ventilation/47179498
Cohort management and wellbeing
The central concern of Dr. Moore is wellbeing but infection is not mentioned as a part of that wellbeing. The central objective of cohort management and outbreak control is to reduce significant outbreaks of infection, especially when infection prevalence is extreme like it is now.
- Schools had significant outbreaks before Omicron took off. In the first two weeks of December, Ontario schools accounted for 1,757 outbreak cases, 45.9% of total identified outbreak cases in the province. This compared to only 302 in the workplace. School outbreak cases were growing more rapidly than any other category in the first half of December, going from 24 per day on October 21st to 144 on December 14th, a six-fold increase. At that point, Omicron infections were growing but the doubling rate had not yet exploded as cases. (Source: ON govt open data, my charts)
2. Niagara’s reported community Omicron cases are currently averaging 311 per day compared to 20 at the end of November*. That’s a fifteen-fold increase before accounting for the absence of general community testing this year, which, given Omicron’s high Rt, doubling rate projections and transmissibility, may place the current case load at 3–6 times higher. (*ON govt open data).
This extreme level of community prevalence means that students and staff will often enter schools with multiple infections in many classes and, in my opinion, limited ability to control further superspreader outbreaks without at least the modest measures Dr. Hirji proposes. (It was Dr. Moore himself who underlined the importance of cohorts, testing and tracing when the school year began.)
Those events if left unattended will invariably lead to greater household infections and harm more vulnerable people in the community.
3. “Long covid” is not mentioned in Dr. Moore’s letter, yet it is a real concern of many scientists. It is true that children are hospitalized at a lower rate than adults but we should also note that paediatric hospitalizations in the US are at an all-time high and covid is listed among the top ten reasons for death among children.
Using a short-term hospitalization measure alone leaves out the other risks of infection which concern many researchers and doctors. Long covid has to be seriously considered when weighing Dr. Moore’s preference that students’ education or mental health not be temporarily disrupted by additional measures to limit spread.
Almost half of children who contract covid-19 may have lasting symptoms, which should factor into decisions on reopening schools, reports Helen Thomson
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7927578/However, the particularly immunogenic nature of SARSCoV-2 (Lucas et al., 2020), together with the magnitude of people infected during this pandemic, contribute to the emerging crisis of persistent cognitive impairment associated with COVID-19 infection.
https://www.sciencedaily.com/releases/2021/07/210716112443.htm
Medical exemption notes for masking
Since half of Ontario elementary school kids do not have a single dose of vaccine yet and the guidance of top world health authorities is to wear quality masks to help prevent Omicron spread where not legitimately exempt, Dr. Moore’s reluctance to require a medical exemption sign-off is perplexing.
It will undoubtedly lead to more outbreaks and infections by those opposed to mask wearing for non-medical reasons. Given the high prevalence of Omicron right now, I have to support Dr. Hirji on this initiative. Allowing or even encouraging non-mask compliance will only cause more harm than good to our children.
Sincerely,
Bill Comeau
January 20, 2022
[Edits were added to correct names and add a Swiss study.]
