COVID19 COVID-19 - Vaccine Effectiveness
(Ontario, Canada)

This page contains data about COVID-19 vaccine effectiveness in Ontario, Canada.  Most graphs are updated on a daily basis early morning each day.

You can also find COVID-19 stats for Global, Canada, Ontario, and Quebec, City of Ottawa, ON, Canada and Vaccination stats for Canada, Ontario, & Quebec.

Table of Contents

1. Vaccination Status of Ontario
2. Unvaccinated Risk of Infection, Hospitalization, ICU vs Full Vaccinated
3. Cases per 100K Population by Vaccine Status and Age
4. # Hospitalized (Non-ICU) per 100K Population by Vaccine Status
5. # Hospitalized (ICU) per 100K Population by Vaccine Status
6. Vaccine Effectiveness by Age

Vaccination Status of Ontario

In order to properly understand vaccine effectiveness in Ontario, people need to know the number and what proportion of the the population is vaccinated.  The following graphs show the vaccination status of the population of Ontario.  You can find more detailed stats on vaccination status and vaccine safety on the Vaccination stats for Canada, Ontario, & Quebec page.  Ontario population stats are taken from Statistics Canada and vaccination status from Ontario.




Unvaccinated Risk of Infection, Hospitalization, ICU vs Fully Vaccinated

The boxes below display relative increase in infections and number of people hospitalized and in the ICU per 100K population of unvaccinated people compared to fully vaccinated people in Ontario.  The second row shows the vaccine effectiveness against infection and hospitalization (Non-ICU & ICU) showing the reduction associated with full vaccination.  Please note it is very important to take population size into account since the majority of people are vaccinated to properly compared against unvaccinated cases.  You can read more about this importance, along with importance of stratifying data by age, and taking into account Simpson's paradox in this article by Jeffrey Morris.  Data source Ontario Cases and Ontario Hospitalization rates.







1 in unvaccinated Ontarians are currently hospitalized (Non-ICU).

1 in vaccinated Ontarians are currently hospitalized (Non-ICU).

1 in unvaccinated Ontarians are currently in the ICU.

1 in vaccinated Ontarians are currently in the ICU.


Cases per 100K Population by Vaccine Status and Age

The graphs below show the 7-day average daily number of COVID-19 cases in Ontario by vaccine status and stratified by age per 100K population and percentage share of cases per 100K. Please note it is very important to take population size into account since the majority of people are vaccinated to properly compare against unvaccinated cases.  You can read more about the importance of taking into account population size, stratifying data by age, and taking into account Simpson's paradox in this article by Jeffrey Morris. Data source: Ontario

Cases per 100K population by vaccine status and age were available until Oct 24, 2021 before technical difficulties stopped new data being published.


# Hospitalized (Non-ICU) per 100K Population by Vaccine Status

The graphs below show the daily current # of COVID-19 hospitalizations (Non-ICU) in Ontario by vaccine status per 100K population and percentage share of hospitalizations (Non-ICU) per 100K. Please note it is very important to take population size into account since the majority of people are vaccinated to properly compare against unvaccinated cases.  While it is also important to stratify by age, daily age data is not currently available from the province so vaccine effectiveness would be even more accurately represented for the different age groups if this was available.  You can read more about the importance of taking into account population size, stratifying data by age, and taking into account Simpson's paradox in this article by Jeffrey Morris. Data source: Ontario


# Hospitalized (ICU) per 100K Population by Vaccine Status

The graphs below show the daily current # of COVID-19 hospitalizations (ICU) in Ontario by vaccine status per 100K population and percentage share of hospitalizations (ICU) per 100K. Please note it is very important to take population size into account since the majority of people are vaccinated to properly compare against unvaccinated cases.  While it is also important to stratify by age, daily age data is not currently available from the province so vaccine effectiveness would be even more accurately represented for the different age groups if this was available.  You can read more about the importance of taking into account population size, stratifying data by age, and taking into account Simpson's paradox in this article by Jeffrey Morris. Data source: Ontario


Vaccine Effectiveness by Age

The graphs below show the effectiveness of the COVID-19 vaccines used in Ontario by age, displaying what % of positive cases result in hospitalization, ICU admission, or death in each of those three populations since December 14, 2020 when vaccination started..  This will not add up to 100% since it is just the portion of cases impacted. Source of data comes from the Public Health Ontario.

Partially vaccinated is defined as someone who is 14 or more days following the first dose of a 2-dose COVID-19 vaccine or 0 to less than 14 days after receiving the second dose.

Fully vaccinated is defined as someone who is 14 or more days following the second dose of a 2-dose COVID-19 vaccine.

Unvaccinated is defined as someone who has received 0 doses of a COVID-19 vaccine or 0 to less than 14 days after receiving the first dose of a 2-dose COVID-19 vaccine, before protection starts.


The way read these first 3 graphs is to find your age group and look at the three categories (Unvaccinated, Partially Vaccinated, Fully Vaccinated).  Choose the category that you are interested in and look at the percentage.  That is the percentage of people in that category who tested positive for COVID-19 and then ended up being hospitalized/admitted to ICU/died since December 14, 2020 when vaccination started. For example, if you are looking at hospitalization for people 80+ and the unvaccinated percentage is 31%, that means 31% of unvaccinated people who tested positive for COVID-19 infection aged 80+ were hospitalized.

The next three graphs provide a different view, showing the distribution of symptomatic and asymptomatic cases, hospitalizations, and deaths for people who were partially vaccinated, fully vaccinated, and unvaccinated since December 14, 2020 when vaccination started which add up to 100%.  Please note these graphs show the view over a wide period of time so the overall effectiveness starting when very few people were vaccinated.  It does *not* show the recent effectiveness of the vaccines which are impacted by the number of cases in the community and types of variants people are being infected with.



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