Post

Tara Moriarty

@MoriartyLab

Oct 22, 2023 • 60 tweets • 17 min read • Read on X

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Canadian COVID Forecast: Oct 21-Nov 3, 2023

SEVERE: CAN, AB, BC, MB, NB, NL, North, NS, ON, PEI, QC, SK
VERY HIGH: none
HIGH: none
ELEVATED: none
MODERATE: none
LOW: none

About 1 in 19 people in Canada are CURRENTLY infected.

Prévisions de COVID pour le Canada: 21 oct - 3 nov, 2023

EXTRÊME: CAN, AB, CB, MB, NB, TNL, Nord, NÉ, ON, ÎPÉ, QC, SK
GRAVE: aucun
TRÈS ÉLEVÉ: aucun
ÉLEVÉ: aucun
MODÉRÉ: aucun
FAIBLE: aucun

Environ 1 personne sur 19 au Canada est actuellement infectée

Studies show even Mild Covid can have long term effects. #MasksKeepUsSafe.

Graphic is courtesy of BIRCH, @BIRcovidhealth, used with permission.

@BIRcovidhealth THREAD OUTLINE:

- Links to data sources, resources

- What’s new this week?

-Current COVID Forecasts by province

@BIRcovidhealth PLAN DU FIL:

- Liens vers des sources de données et des ressources

- Quoi de neuf cette semaine ?

@BIRcovidhealth -Prévisions actuelles du COVID par province

Information about methods, forecast inputs, estimated infections, long COVID cases, hospital and ICU admissions and deaths is available in our biweekly report at link here:

covid19resources.ca/covid-hazard-i…

@BIRcovidhealth Des infos sur les méthodes, prévisions, infections estimées, cas de COVID à long terme, admissions dans les hôpitaux et soins intensifs et décès sont disponibles dans notre rapport bihebdomadaire ici:

covid19resources.ca/covid-hazard-i…

@BIRcovidhealth Information about excess mortality in every Canadian province is available in our monthly report at link here:

covid19resources.ca/public/excess-…

@BIRcovidhealth Des informations sur la surmortalité dans chaque province canadienne sont disponibles dans notre rapport mensuel en cliquant ici :

covid19resources.ca/public/excess-…

@BIRcovidhealth Do you have questions about:

-this week’s forecast
-COVID
-vaccines
-masks
-risks of specific activities

We can help!

You can join one of our free evening Zoom sessions by signing up at the link here:

covid19resources.ca/discussions/

@BIRcovidhealth Vous avez des questions?

-les prévisions
-COVID
-les vaccins
-les masques
-les risques liés à certaines activités

Nous pouvons vous aider!

Vous pouvez participer à l'une de nos sessions Zoom gratuites en vous inscrivant ici:

covid19resources.ca/discussions/

@BIRcovidhealth Do you want to see how the forecast is changing as new data come in?

You can go to the Forecast Inputs page of the report (p11). Most pages of the report are live. We enter data on Wed, Fri and Sat each week.

covid19resources.ca/covid-hazard-i…

@BIRcovidhealth Vous souhaitez voir comment la prévision évolue de l'arrivée de nouvelles données?

Vous pouvez consulter la page "Forecast Inputs" du rapport (p11). La plupart des pages du rapport sont en direct.

covid19resources.ca/covid-hazard-i…

@BIRcovidhealth WHAT’S NEW THIS WEEK?

About 1 in 19 people in Canada are currently infected.

Estimated infections are at/nearing peak of all previous Omicron waves except Dec/21 wave.

5-week averages for waste water for all Canadian sites from @GovCanHealth are increasing 27%/week.

@BIRcovidhealth @GovCanHealth We think mortality in Canada from this wave may reach the height of deaths from all previous COVID-19 waves in the pandemic to date, unless those at greatest risk of death from COVID-19 get their boosters ASAP.

@BIRcovidhealth @GovCanHealth Forecast scores before Aug/23 under-predicted mortality.

From @CIHI_ICIS released Sep/23 we know under-reporting of hospital and ICU admissions is greater than we estimated.

Scores from Aug/23 onward are corrected to reflect current under-reporting rates.

@BIRcovidhealth @GovCanHealth @CIHI_ICIS Due to inconsistent provincial reporting, this week we switched to hospital, ICU and death data from @GovCanHealth and @INSPQ, corrected for under-reporting.

Forecast scores reflect regional differences in population size, waste water and estimated infections.

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ From @CIHI_ICIS we know 35% of hospital and 83% of ICU admissions for Jan-Mar/23 were NOT reported to @GovCanHealth.

Current numbers are likely one third higher than @GovCanHealth report.

health-infobase.canada.ca/covid-19/curre…

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ You may also notice scores of 25 for multiple indicators and provinces. This is because we set a max of 25 to stabilize the global (overall) score.

The overall score reflects the % excess mortality we think will result from infections…

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ In Canada, we have not typically seen excess mortality peaks greater than 25-30% during Omicron.

When we get the next excess mortality report from @statcan_eng in mid-Nov we will revisit whether to set the max higher than 25.

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Environ 1 personne sur 19 est actuellement infectée au Canada.

Les infections estimées atteignent ou approchent le pic de toutes les vagues Omicron précédentes, à l'exception de la vague du déc/21.

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Les moyennes sur 5 semaines pour les eaux usées de tous les sites canadiens de @GovCanHealth augmentent de 27%/semaine.

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Nous pensons que la mortalité due à cette vague pourrait atteindre le niveau des décès de toutes les vagues précédentes, à moins que les personnes les plus au risque de décès dû à COVID-19 ne reçoivent leurs vaccins de rappel dès que possible.

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Les résultats des prévisions avant le août/23 sous-estimaient la mortalité.

D'après @CIHI_ICIS données publiées le sep/23, nous savons que la sous-déclaration des admissions…

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng …dans les hôpitaux et les unités de soins intensifs est plus importante que nous ne l'avions estimé.

Les scores à partir du 23 août sont corrigés pour refléter les taux actuels de sous-déclaration.

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng En raison de l'incohérence des rapports provinciaux, cette semaine nous avons utilisé les données sur les hôpitaux, les unités de soins intensifs et les décès provenant de @GovCanHealth et @INSPQ, corrigées pour tenir compte de la sous-déclaration.

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Les résultats des prévisions reflètent les différences régionales dans la taille de la population, les eaux usées et les infections estimées.

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Grâce à @CIHI_ICIS, nous savons que 35 % des admissions à l'hôpital et 83 % des admissions en USI pour janvier-mars-23 n'ont PAS été déclarées à @GovCanHealth.

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Les chiffres actuels sont probablement un tiers plus élevés que ceux rapportés par @GovCanHealth.

health-infobase.canada.ca/covid-19/curre…

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Vous pouvez également remarquer des scores de 25 pour plusieurs indicateurs et provinces. Cela s'explique par le fait que nous avons fixé un maximum de 25 pour stabiliser le score global.

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Le score global reflète le pourcentage de surmortalité que nous pensons résulter des infections.

Au Canada, nous n'avons pas observé de pics de surmortalité supérieurs à 25-30 % pendant Omicron.

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Lorsque nous recevrons le prochain rapport de surmortalité de @statcan_eng à la mi-novembre, nous réexaminerons la possibilité de fixer le maximum à plus de 25.

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Canadian COVID Forecast Oct 21-Nov 3, 2023

CANADA

SEVERE (increasing)

About 1 in every 19 people infected

Compared to lowest point of pandemic in Canada:

-Infections ~25X higher
-Long COVID ~16X higher
-Hospitalizations ~15X higher
-Deaths ~24X higher

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Prévisions de COVID: 21 oct-3 nov, 2023

CANADA

EXTRÊME (en hausse)

Environ 1 personne sur 19 est infectée

Par rapport au point le plus bas de la pandémie au Canada:

-Infections ~25X supérieur
-COVID longue ~16X supérieur
-Hospitalisations ~15X supérieur
-Décès ~24X supérieur

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Canadian COVID Forecast Oct 21-Nov 3, 2023

NEWFOUNDLAND AND LABRADOR

SEVERE (no change)

About 1 in every 21 people infected

Compared to lowest point of pandemic in Canada:

-Infections ~18X higher
-Long COVID ~14X higher
-Hospitalizations ~13X higher
-Deaths ~23X higher

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Prévisions de COVID: 21 oct - 3 nov, 2023

TERRE-NEUVE ET LABRADOR

EXTRÊME (stable)

Environ 1 personne sur 21 est infectée

Par rapport au point le plus bas de la pandémie au Canada:

-Infections ~18X🔺
-COVID longue ~14X🔺
-Hospitalisations ~13X🔺
-Décès ~23X 🔺

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Canadian COVID Forecast Oct 21-Nov 3, 2023

PRINCE EDWARD ISLAND

SEVERE (increasing)

About 1 in every 17 people infected

Compared to lowest point of pandemic in Canada:

-Infections ~25X higher
-Long COVID ~17X higher
-Hospitalizations ~12X higher
-Deaths ~25X higher

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Prévisions de COVID pour le Canada: 21 oct - 3 nov, 2023

ÎLE DU PRINCE ÉDOUARD

EXTRÊME (en hausse)

Environ 1 personne sur 17 est infectée

Par rapport au point le plus bas de la pandémie au Canada:

-Infections ~25X🔺
-COVID longue ~17X🔺
-Hospitalisations ~12X🔺
-Décès ~25X🔺

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Canadian COVID Forecast Oct 21-Nov 3, 2023

NOVA SCOTIA

SEVERE (no change)

About 1 in every 15 people infected

Compared to lowest point of pandemic in Canada:

-Infections ~25X higher
-Long COVID ~19X higher
-Hospitalizations ~16X higher
-Deaths ~25X higher

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Prévisions de COVID pour le Canada: 21 oct - 3 nov, 2023

NOUVELLE-ÉCOSSE

EXTRÊME (stable)

Environ 1 personne sur 15 est infectée

Par rapport au point le plus bas de la pandémie au Canada :

-Infections ~25X🔺
-COVID longue ~19X🔺
-Hospitalisations ~16X🔺
-Décès ~25X🔺

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Canadian COVID Forecast Oct 21-Nov 3, 2023

NEW BRUNSWICK

SEVERE (no change)

About 1 in every 10 people infected

Compared to lowest point of pandemic in Canada:

-Infections ~25X higher
-Long COVID ~25X higher
-Hospitalizations ~19X higher
-Deaths ~25X higher

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Prévisions de COVID: 21 oct - 3 nov, 2023

NOUVEAU BRUNSWICK

EXTRÊME (stable)

Environ 1 personne sur 10 est infectée

Par rapport au point le plus bas de la pandémie au Canada :

-Infections ~25X🔺
-COVID longue ~25X🔺
-Hospitalisations ~19X🔺
-Décès ~25X🔺

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Canadian COVID Forecast Oct 21-Nov 3, 2023

QUÉBEC

SEVERE (increasing)

About 1 in every 18 people infected

Compared to lowest point of pandemic in Canada:

-Infections ~25X higher
-Long COVID ~16X higher
-Hospitalizations ~12X higher
-Deaths ~24X higher

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Prévisions de COVID: 21 oct - 3 nov, 2023

QUÉBEC

EXTRÊME (en hausse)

Environ 1 personne sur 18 est infectée

Par rapport au point le plus bas de la pandémie au Canada :

-Infections ~25X🔺
-COVID longue ~16X🔺
-Hospitalisations ~12X🔺
-Décès ~24X🔺

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Canadian COVID Forecast Oct 21-Nov 3, 2023

ONTARIO

SEVERE (increasing)

About 1 in every 23 people infected

Compared to lowest point of pandemic in Canada:

-Infections ~18X higher
-Long COVID ~13X higher
-Hospitalizations ~11X higher
-Deaths ~20X higher

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Prévisions de COVID: 21 oct - 3 nov, 2023

ONTARIO

EXTRÊME (en hausse)

Environ 1 personne sur 23 est infectée

Par rapport au point le plus bas de la pandémie au Canada :

-Infections ~18X🔺
-COVID longue ~13X🔺
-Hospitalisations ~11X🔺
-Décès ~20X🔺

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Canadian COVID Forecast Oct 21-Nov 3, 2023

MANITOBA

SEVERE (increasing)

About 1 in every 16 people infected

Compared to lowest point of pandemic in Canada:

-Infections ~25X higher
-Long COVID ~19X higher
-Hospitalizations ~16X higher
-Deaths ~25X higher

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Prévisions de COVID: 21 oct - 3 nov, 2023

MANITOBA

EXTRÊME (en hausse)

Environ 1 personne sur 16 est infectée

Par rapport au point le plus bas de la pandémie au Canada :

-Infections ~25X🔺
-COVID longue ~19X🔺
-Hospitalisations ~16X🔺
-Décès ~25X🔺

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Canadian COVID Forecast Oct 21-Nov 3, 2023

SASKATCHEWAN

SEVERE (increasing)

About 1 in every 16 people infected

Compared to lowest point of pandemic in Canada:

-Infections ~25X higher
-Long COVID ~19X higher
-Hospitalizations ~12X higher
-Deaths ~25X higher

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Prévisions de COVID: 21 oct - 3 nov, 2023

SASKATCHEWAN

EXTRÊME (en hausse)

Environ 1 personne sur 16 est infectée

Par rapport au point le plus bas de la pandémie au Canada :

-Infections ~25X🔺
-COVID longue ~19X🔺
-Hospitalisations ~12X🔺
-Décès ~25X🔺

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Canadian COVID Forecast Oct 21-Nov 3, 2023

ALBERTA

SEVERE (increasing)

About 1 in every 15 people infected

Compared to lowest point of pandemic in Canada:

-Infections ~25X higher
-Long COVID ~20X higher
-Hospitalizations ~17X higher
-Deaths ~25X higher

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Prévisions de COVID: 21 oct - 3 nov, 2023

ALBERTA

EXTRÊME (en hausse)

Environ 1 personne sur 15 est infectée

Par rapport au point le plus bas de la pandémie au Canada :

-Infections ~25X🔺
-COVID longue ~20X🔺
-Hospitalisations ~17X🔺
-Décès ~25X🔺

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Canadian COVID Forecast Oct 21-Nov 3, 2023

BRITISH COLUMBIA

SEVERE (no change)

About 1 in every 14 people infected

Compared to lowest point of pandemic in Canada:

-Infections ~25X higher
-Long COVID ~20X higher
-Hospitalizations ~16X higher
-Deaths ~25X higher

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Prévisions de COVID: 21 oct - 3 nov, 2023

COLOMBIE BRITANNIQUE

EXTRÊME (stable)

Environ 1 personne sur 14 est infectée

Par rapport au point le plus bas de la pandémie au Canada :

-Infections ~25X🔺
-COVID longue ~20X🔺
-Hospitalisations ~16X🔺
-Décès ~25X🔺

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Canadian COVID Forecast Oct 21-Nov 3, 2023

NUNAVUT, NWT, YUKON

SEVERE (increasing)

About 1 in every 20 people infected

Compared to lowest point of pandemic in Canada:

-Infections ~18X higher
-Long COVID ~19X higher
-Hospitalizations ~16X higher
-Deaths ~23X higher

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Prévisions de COVID: 21 oct - 3 nov, 2023

NUNAVUT, TNO, YUKON

EXTRÊME (en hausse)

Environ 1 personne sur 20 est infectée

Par rapport au point le plus bas de la pandémie au Canada :

-Infections ~18X🔺
-COVID longue ~19X🔺
-Hospitalisations ~16X🔺
-Décès ~22X🔺

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Remember, the forecast reflects not only recent input data, but also numbers expected for the next 2 weeks, based on 5-week average trends.

The next forecast will be November 4, 2023.

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng N'oubliez pas que les prévisions reflètent non seulement les données récentes, mais aussi les chiffres attendus pour les deux semaines à venir, sur la base des tendances moyennes sur cinq semaines.

La prochaine prévision sera disponible le 4 novembre 2023.

@BIRcovidhealth @GovCanHealth @CIHI_ICIS @INSPQ @StatCan_eng Thanks to @netgaines @CircaLiz @BattlingBeaver @lamarche_denise for data input, graphics and translation.

Thanks to the whole @covid_19_canada team for weekly feedback and for keeping all our work going. #TogetherWeCan

Merci à @netgaines @CircaLiz @BattlingBeaver @lamarche_denise pour la saisie des données, les graphiques et la traduction.

Merci à toute l'équipe de @covid_19_canada pour les commentaires hebdomadaires et pour la poursuite de notre travail.

#EnsembleNousPouvons

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More from @MoriartyLab

Tara Moriarty

@MoriartyLab

Oct 9

With the transition of Canadian COVID-19 reporting to the combined respiratory virus dashboard, weekly COVID-19 deaths for Canada are no longer publicly reported by @GovCanHealth .

According to the most recent report, participating provinces reported 971 hospitalizations and 131 deaths for the period from Aug 25-Sep 28/24.

During the same period, Quebec, which accounts for 22% of the Canadian population, reported 4,691 hospitalizations and 256 deaths (current INSPQ data).

If hospitalizations and deaths are similar in Quebec and the rest of Canada (likely), the national report for the Aug 25-Sep 28/24 period should include at least 21,323 hospitalizations and 1,164 deaths.

Based on the most recent @CIHI_ICIS reporting of Quebec in-hospital COVID-19 deaths (Apr 1/22 to Mar 31/23), there were 1.28 times more documented COVID deaths in QC hospitals than were reported by INSPQ for the same period. However, CIHI captured only 84% of INSPQ-reported hospitalizations in QC for this period, meaning QC in-hospital deaths were likely ~1.52 times higher than deaths reported by INSPQ.

About 70% of all deaths in QC occur in hospitals (StatsCan), meaning actual COVID deaths were likely ~2.17 times higher in QC than reported by INSPQ, at least from Apr 1/22 to Mar 31/23.

Is QC reporting only "from" COVID deaths and excluding deaths of people who would have died anyway from other causes?

To test this, we can compare excess mortality estimates from @StatCan_eng for the same period, after correcting them to remove excess mortality attributable to toxic drug deaths and excess cancer deaths (stand-in for potential excess mortality attributable to delays in access to healthcare and MAID).

The StatsCan excess mortality program has been paused for the last 10 months, so estimates for QC are only available up to Sep 2/23, and are still incomplete for weeks before this date.

However, weekly age-adjusted per capita all-cause mortality rates for QC and other provinces are still published every month, meaning weekly excess mortality can still be estimated by comparing weekly mortality rates in one year to mortality rates in the same week of the preceding year, and using these ratios to estimate current excess mortality values compared to previous years when estimates are more complete.

From Apr 1/22 to Mar 31/23, there were 2.19 times more excess deaths in Quebec than reported COVID deaths, after adjusting for excess mortality attributable to toxic drugs and cancer.

This is very close to the CIHI-based estimate of actual COVID-19 deaths (2.17 times higher than reported by INSPQ for Apr 1/22 to Mar 31/23).

Taking the average of both methods for estimating under-reporting in QC, we know that for the year ending Mar 31/23, INSPQ reported 46% of "excess/from" COVID-19 deaths.

If we assume the magnitude of under-reporting of COVID-19 deaths by Quebec was similar after Mar 31/23, then from Aug 25-Sep 28/24 there were likely 558 excess/from COVID-19 deaths in Quebec, and 2,537 COVID-19 deaths in Canada.

Recall, the total number of COVID-19 deaths in Canada from Aug 25-Sep 28/24 reported on the new respiratory virus surveillance dashboard from PHAC: 131

So, it's likely that the new national COVID-19 dashboard is reporting, ~5% of "excess/from" COVID-19 deaths in Canada.

However, reporting of COVID-19 deaths by Quebec has actually worsened since Mar 31/23.

How do we know this? Because from Apr 1/23 to Jun 8/24 (the last date when age-adjusted all cause mortality rates are available from StatsCan), there were 6.37 excess deaths for every COVID-19 death reported by INSPQ, after adjusting for excess mortality attributable to toxic drugs and cancer.

So, from April 1/23 onward, Quebec has likely been reporting only 16% of its COVID-19 deaths.

If the under-reporting rate for Aug 25-Sep 28/24 was the same as for Apr 1/23 to Jun 8/24, then there were likely 1,630 "excess/from" COVID-19 deaths in Quebec from Aug 25-Sep 28/24, and 7,407 "excess/from" COVID-19 deaths in Canada during the same period.

Recall, the total number of COVID-19 deaths in Canada from Aug 25-Sep 28/24 reported on the new respiratory virus surveillance dashboard from PHAC: 131

So, it's likely that the new national COVID-19 dashboard is reporting, fewer than 2% of "excess/from" COVID-19 deaths in Canada for the 2024 respiratory virus season to date.

And no, Canada doesn't have exceptionally high COVID-19 mortality rates.

From December 2021 to March 2023, the estimated median weekly COVID-19 infection fatality rate for Canada was 4% LOWER than the median infection fatality rate for the UK calculated from ONS infection estimates and confirmed COVID-19 deaths, even though Canada is slightly older than the UK and has had lower rates of fresh vaccine dose uptake than the UK from 2022 onward.

What was the median weekly SARS-CoV-2 infection fatality rate for Canada during this period? 0.08747%

What was it in the UK? 0.08824%

Open access ref for UK IFRs: ncbi.nlm.nih.gov/pmc/articles/P…

Why are so few of Canada's COVID-19 deaths reported?

It's likely that at least in part it's because many/most(?) provinces now only report deaths in people infected for the first time, as @sarperotto has confirmed for BC via official communications from BCCDC.

From Dec 4/21 to date, the average person in Canada has had ~3.5 SARS-CoV-2 infections. Reporting only deaths associated with first time infections would reduce reporting by ~70%....meaning only ~30% of deaths would have been reported if this policy was in place in every province.

On top of that, testing in Canada during Omicron has declined ten times more than the decrease in infection and fatality rates, meaning that a substantial number of deaths and hospitalizations simply wouldn't be detected because of under-testing.

So, it's probably a combined issue of under-reporting and under-testing, but either way, it's an enormous problem.

As the Office of Canada's Chief Science Advisor Dr. Mona Nemer @ChiefSciCan has pointed out, Canada currently has gaps in the effectiveness of our communication about COVID-19 vaccines. Fewer than 15% of people in Canada got fresh doses in the fall 2023 campaign.

Perhaps if we started reporting more than 2% of actual COVID-19 deaths on our new national respiratory virus reporting dashboard people would better understand why getting a fresh vaccine is so important, and journalists would have real numbers they can use to help communicate about the issue.

I don't know who else to copy in on this post--it's like shouting into the wind, and I don't know what it will take for Canada and ALL provinces to start improving actual COVID-19 deaths and hospitalizations.

@picardonhealth @NightShiftMD @DrGorfinkel maybe you can help resurrect a national conversation on this topic.

Should also copy in @CBCQueensPark, who's still following official public communication about COVID-19 vaccines, or rather, the near absence of official communication about their importance.

Sorry for the oversight, Mike.

Adding to this post after seeing some comments/questions.

1. Some provinces just may be reporting extremely slowly to PHAC, so it's possible those numbers may still come up.....but they'd have to come up a LOT to match what is expected, if fewer than 2% of actual deaths are being reported.

2. Quebec hospitalizations are almost certainly under-reported too. It's likely it's not under-reporting so much as under-testing.

In the UK, during Omicron, there were 5.16 reported COVID-19 hospitalizations for every reported COVID-19 death. That's a mortality rate for hospitalized cases of 19%, which is about 5 times higher than mortality rates for all non-COVID-19 causes of hospitalization in Canada.

However, UK-reported COVID-19 hospitalizations per COVID-19 death are about half the number of hospitalizations per death reported by France, about half the admissions/death ratio reported by CIHI for Canada from 2022-2023, and about half the number of hospitalizations per death reported by Quebec up to March 31, 2022. Canada and the UK have some of the lowest numbers of hospital beds per capita of any OECD country, so the UK may admit fewer people with COVID, even though the mortality rate is high. Hospitalizations are also defined very tightly to include respiratory codes, which likely excludes COVID cases without respiratory codes in patient charts.

If we take the average hospitalizations per death reported by France during Omicron (France was historically an excellent reporter for COVID hospitalizations), by CIHI for Canada from 2022-2023 and by Quebec for Omicron up to March 31, 2022, then we would expect ~9.4 hospitalizations for every death.

For Aug 25-Sep 28/24, when there were an estimated 1,630 COVID deaths in Quebec, we'd expect 15,322 hospitalizations. However, 4691 were reported for this period. This means that about 31% of expected Quebec COVID hospitalizations are currently being reported.

And we would have expected 69,645 reported hospitalizations for Canada. Recall the number reported during this period on the new dashboard: 971

So, likely fewer than 2% of COVID-19 hospitalizations for Canada are being reported on the new dashboard--similar to the proportion of COVID deaths reported.

Again, this may be under-reporting--and it certainly is for many provinces. For Quebec I don't think it's under-reporting of known hospitalizations so much as under-detection of COVID-19 in people who are hospitalized, because of under-testing. And Quebec still tests considerably more per capita than other provinces.

Finally, it's possible that fewer than 2% of the expected 69,645 COVID-19 hospitalizations in Canada were reported for Aug 25-Sep 28, 2024 not just because of under-reporting and under-testing, but also because some provinces may simply be admitting far fewer people with COVID-19 to hospital.

The number of people who report receiving Paxlovid in Canada is almost negligible, so it's not because we're able to avoid admissions because we're prescribing a helpful drug that's now available to help prevent hospitalization. And most people who need to be hospitalized with COVID need hospitalization more than one week after symptom onset--too late for Paxlovid.

Read 4 tweets

Tara Moriarty

@MoriartyLab

Sep 29

Canadian COVID Forecast: Sep 28-Oct 11, 2024

SEVERE: CAN, BC, MB, NB, North, NS, ON, QC, SK
VERY HIGH: NL, PEI
HIGH: AB
MODERATE: none

About 1 in 38 people in Canada are CURRENTLY infected.

https://x.com/MoriartyLab/status/1840537268852777150

Notre aperçu national en français :

https://x.com/MoriartyLab/status/1840537268852777150

https://x.com/michael_hoerger/status/1838075513430016207

WHAT'S NEW THIS WEEK?

The Forecast score for Canada is decreasing 7%/week (-14% to -2%/week for all regions).

About 1 in 38 people are currently infected (~147,000 infections/day).

This is similar to the Sep 23 estimate for the United States (1 in 45) from @michael_hoerger and team:

https://x.com/michael_hoerger/status/1838075513430016207

Read 13 tweets

Tara Moriarty

@MoriartyLab

Sep 29

Canadian COVID Forecast Sep 28-Oct 11, 2024

CANADA

SEVERE (decreasing)

Estimated infections this week: 962,700-1,097,900

About 1 in every 38 people infected

Compared to lowest point of pandemic in Canada:

-Infections ~16X higher
-Long COVID ~15X higher
-Hospitalizations ~15X higher
-Deaths ~17X higher

https://x.com/MoriartyLab/status/1840536770607562888

Prévisions régionales sur la COVID-19 se trouvent ici :

https://x.com/MoriartyLab/status/1840536770607562888

Canadian COVID Forecast Sep 28-Oct 11, 2024

NEWFOUNDLAND AND LABRADOR

VERY HIGH (no change)

Estimated infections this week: 13,000-15,000

About 1 in every 38 people infected

Compared to lowest point of pandemic in Canada:

-Infections ~15X higher
-Long COVID ~14X higher
-Hospitalizations ~12X higher
-Deaths ~14X higher

Read 16 tweets

Tara Moriarty

@MoriartyLab

Sep 28

School Classrooms and Masks and Air

School Classrooms and Masks and Air
Last week we offered a cornucopia of information about infection risks in the classroom.

This week we’re using the same data, and presenting a clear picture of the best ways to keep everyone safer while they are in school.

-FYI- This thread is also available on the C-19 website, starting on page 8, for easier reading.

lookerstudio.google.com/embed/u/0/repo…

Anecdotally, there’s a lot of chatter about absenteeism and staff shortages already this school year. Even with the ongoing pandemic, there’s no need for children and education workers to be sick all the time.

We can make our classrooms safer.

Spoiler alert: The data is clear, masking protects the most vulnerable and by doing so, protects everyone.

The Data Cards now model going to school in 3 different conditions: children wearing fit tested N95, regular N95 for little kids, or unmasked.

For those 3 conditions, the model also shows two kinds of school – schools with HVAC, those schools without HVAC. Lastly, the model shows the effects of including portable air purifiers in the classroom. We modelled Corsi-Rosenthal boxes, but tested Merv13 or HEPA filters also work.

This shift in presenting the data gives us a striking picture of risk progressions.

The story the Data Cards tell is that the most important thing you can do to protect your children is to put them in a well-fitting mask.

Masks reduce risk 100- fold, no matter the school ventilation situation.

Masks drive the risk down for your family dramatically.

Read 15 tweets

Tara Moriarty

@MoriartyLab

Sep 15

Prévisions de COVID pour le Canada : SEP 14-27, 2024

CANADA

GRAVE (en baisse)

Infections pendant cette période : 1 031 400-1 095 400

Environ 1 personne sur 37 est infectée

Par rapport au point le plus bas de la pandémie au Canada :

-Infections ~18X 🔺
-COVID longue ~18X 🔺
-Hospitalisations ~17X 🔺
-Décès ~22X 🔺

https://x.com/MoriartyLab/status/1830331164663407040

The english version of our regional forecast can be found here:

https://x.com/MoriartyLab/status/1830331164663407040

Prévisions de COVID pour le Canada : SEP 14-27, 2024

TERRE-NEUVE ET LABRADOR

TRÈS ÉLEVÉ (en baisse)

Infections pendant cette période : 7 500-8 000

Environ 1 personne sur 63 est infectée

Par rapport au point le plus bas de la pandémie au Canada :

-Infections ~10X🔺
-COVID longue ~11X🔺
-Hospitalisations ~13X🔺
-Décès ~19X🔺

Read 18 tweets

Tara Moriarty

@MoriartyLab

Sep 1

A few things that might help people understand differences in Canadian COVID Forecast scores across provinces....

I'll focus on comparing Alberta and British Columbia, since I get asked a lot why Alberta's scores aren't as high as BC scores in the summer, even though the provinces are adjacent.

In BC, most people live in parts of the province with winters that are considerably warmer than most provinces in Canada, including Alberta.

Even southern Alberta has MUCH colder winters than the BC lower mainland, and cooler spring and fall too. I know. I've lived in both the BC lower mainland and Calgary, and couldn't get over how summer in Calgary didn't seem to really start until July.

This graph shows infections/100K people per day in BC (pink), AB (teal) and Canada (blue) since Dec 4/21.

All provinces have essentially had the same number of infections since then--the timing of when they happened just differs.

Something you'll notice about BC is that fall/winter waves often aren't as big as in Alberta or the rest of Canada.

But....infection waves are bigger in BC from spring-summer.

This is likely because infections don't start taking off till mid-summer in other provinces because there's immunity from the fall-winter infections that hasn't worn off enough until then so that people are susceptible to a new infection.

It's sort of like the brakes have been applied to new infections after the big fall/winter wave in most province, and the pressure on those brakes starts getting lighter toward mid-summer, when infections pick up again.

It's a bit different in BC, since there historically haven't been quite as many infections in the fall/winter waves, which means the population is susceptible to new infections earlier than in colder provinces.

So, in spring and especially summer BC infections tend to take off sooner than in the rest of Canada. By contrast, in winter infections are often lower in BC.

I think we're basically seeing seasonal forcing of infections in most provinces that doesn't affect BC as much because most of the population lives in a more temperature climate.

In most of Canada, there has always been a strong seasonal forcing effect on influenza seasons--stronger than in many more temperature countries, and I suspect that's what we're seeing in most Canadian infection data except those from BC.

Scores can also differ between provinces because of intrinsic differences in population susceptibility to serious outcomes.

Alberta is the youngest province in Canada, and now that uptake of fresh vaccine doses is abysmal across Canada (AB had higher uptake than ON this past season, for example), differences in things like infection fatality and hospitalization rates between provinces are strongly driven by things we can't control, like the average age of the population and rates of underlying health issues.

So, even if AB and BC had exactly the same number of infections in the same week, the Forecast score for Alberta would be slightly lower than the score for BC, because Alberta is younger than BC.

It's also why scores for some Atlantic provinces, particularly Newfoundland and Labrador can be a fair bit higher than the Canadian average.

Newfoundland and Labrador is particularly strongly affected by this because the population is considerably older, plus higher rates of underlying health issues, plus an acute healthcare system that doesn't function quite as well as in big provinces at treating things like heart attacks (probably translating also to treatment of COVID).

And smaller provinces have suffered from poaching of healthcare staff to larger provinces that can pay more.

So, it's not always just about number of infections either. Populations differ in their susceptibility to COVID, and outcomes per infection in Canada range from the highest number of serious outcomes per infection in NL and the lowest in Alberta.

Hope this helps.

Actually, one more thing about BC.

BC is somewhat younger than QC. Its life expectancy is similar--somewhat less than QC now.

QC, followed by BC has the highest life expectancy in Canada, which means that on average the populations in these provinces are generally healthier than populations in other provinces.

Vaccination rates are also generally similar in both provinces, dating back to the start of vaccine availability.

So, infection fatality and hospitalization rates should be pretty similar in both provinces.

However, BC reports fewer than half the hospitalizations per infection than QC, and about a third of the deaths per infection as QC.

Part of this certainly reflects reporting differences between the provinces.

Reporting of serious COVID outcomes in BC has always been considerably lower than in QC, dating back to 2020.

However, the population infection fatality rate (pIFR) for BC calculated from excess mortality is 19% higher than the pIFR for QC, even though QC is slightly older (but also has a slightly healthier population).

By comparison, the pIFR for Ontario is 4% lower than for QC, pretty similar to what you'd expect based on the difference in ages of QC and ON populations.

So why is the BC pIFR higher?

It's not just toxic drugs. We correct for this, and BC actually has more complete, faster toxic drug death reporting than QC.

Plus, the age distribution of excess mortality in QC and BC is pretty similar, with respectively 90% and 80% of excess deaths happening in people 65 and older, as you'd expect for COVID.

It does look like there may be some additional drug deaths in the 45-64 year old age group in BC that aren't yet accounted for, but not enough to explain big differences in the pIFRs in the two provinces.

It is also possible that BC is actually hospitalizing fewer than half the number of people with COVID than are hospitalized in QC, which could certainly contribute to lower survival rates.

That is, maybe BC hospitalizations are much lower than QC hospitalizations not because of under-reporting, but because of "under-treatment" (not sure if that's the right word). Or maybe it's a mix of both under-reporting and under-hospitalization in BC and QC.

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