We broke down the hospitalization risk of going unvaccinated in Ontario. Here’s what the numbers say

Posted on August 18, 2021 in Health Debates

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TheStar.com – GTA
Aug. 16, 2021.   By Ed Tubb, Toronto Star,  Kenyon Wallace, Investigative Reporter

Unvaccinated Ontarians are ending up in hospital with COVID-19 nearly 20 times as often as fully vaccinated individuals and in the last week have been about 70 times more likely to end up in intensive care, a Star analysis of provincial data has found.

While the data analyzed by the Star looks at just one week of hospital admissions (the province only began publishing this information last week) and is not broken down by age, experts say the emerging trend underscores the risks associated with remaining unprotected from a potentially deadly virus.

“The fact that the unvaccinated represent the majority of people being hospitalized or ending up in the ICU is exactly what we would expect to see,” said Todd Coleman, an epidemiologist at Wilfrid Laurier University. “All the science behind the vaccines’ clinical trials is being backed up by what we are seeing here playing out in real life in our population.

“This should be evidence for the unvaccinated that the vaccine works.”

COVID-19 cases by vaccination status

Unvaccinated Ontarians are testing positive for COVID-19 far more often when adjusted by population.
See Chart:  https://www.thestar.com/news/gta/2021/08/16/we-broke-down-the-hospitalization-risk-of-going-unvaccinated-in-ontario-heres-what-the-numbers-say.html?source=newsletter&utm_content=a03&utm_source=ts_nl&utm_medium=email&utm_email=0C810E7AE4E7C3CEB3816076F6F9881B&utm_campaign=reco_68354

The perhaps unsurprising finding that unvaccinated individuals are ending up in hospital and ICUs more than people who have had two shots is playing out at a time when Ontario is now firmly into the beginnings of a fourth wave. Daily case counts have been rising steadily since July 16, the day the province entered Step 3 of its Roadmap to Reopen: the current rolling seven-day average is up to 469 cases per day, more than twice what it was at the beginning of the month.

Week-over-week case growth hasn’t been this fast since September of last year during the early stages of Wave 2. The Star’s Robert Benzie reported Friday that amid the worsening situation, Ontario’s chief medical officer of health, Dr. Kieran Moore, is to announce a pause on further reopening Tuesday, and a requirement that hospital and long-term-care workers be vaccinated.

COVID-19 hospitalizations by vaccination status

Adjusted for population, unvaccinated Ontarians were nearly 20 times more likely to be hospitalized with COVID-19 on an average day last week.
See Chart:  https://www.thestar.com/news/gta/2021/08/16/we-broke-down-the-hospitalization-risk-of-going-unvaccinated-in-ontario-heres-what-the-numbers-say.html?source=newsletter&utm_content=a03&utm_source=ts_nl&utm_medium=email&utm_email=0C810E7AE4E7C3CEB3816076F6F9881B&utm_campaign=reco_68354

The province began publishing hospitalization by vaccination status last Tuesday in simple pie charts that clearly show the vast majority of serious illnesses are occurring among the province’s unvaccinated population. According to the provincial numbers as of Monday, there are more than six times as many unvaccinated patients currently hospitalized with COVID (68) as fully vaccinated individuals (11).

But even this large disparity understates the difference. That’s because while more than four million Ontarians have not yet received their first vaccine dose, the number who are fully vaccinated is much larger: more than 9.5 million. To figure out the overall risk, you need to account for this difference.

Patients in ICU by vaccination status

The greatest difference in COVID-19 outcomes is appearing in the province’s intensive care units. Adjusted for population, unvaccinated Ontarians have been more than 70 times as likely to end up in an ICU.
See Chart:  https://www.thestar.com/news/gta/2021/08/16/we-broke-down-the-hospitalization-risk-of-going-unvaccinated-in-ontario-heres-what-the-numbers-say.html?source=newsletter&utm_content=a03&utm_source=ts_nl&utm_medium=email&utm_email=0C810E7AE4E7C3CEB3816076F6F9881B&utm_campaign=reco_68354

A simple adjustment for the population difference reveals the vaccine’s impact: Over the course of the last week, an unvaccinated Ontarian has been nearly nine times more likely to test positive for COVID than a fully vaccinated individual; they’ve been 19 times more likely to end up in hospital; and at the most serious end, the unvaccinated have gone to the ICU more than 70 times as often as the larger population with both doses.

It’s reasonable, Bogoch said, to assume the risk of hospitalization still skews older, as it has all pandemic, due to the fact that older people are more likely to have additional health conditions that make them vulnerable to infection that would land them in hospital.

Ontario’s unvaccinated population

More than half of Ontario’s 4.1 million unvaccinated people are under age 30 (including ineligible children under 12.) This means the unvaccinated group is much younger than the population as a whole.
See Chart:  https://www.thestar.com/news/gta/2021/08/16/we-broke-down-the-hospitalization-risk-of-going-unvaccinated-in-ontario-heres-what-the-numbers-say.html?source=newsletter&utm_content=a03&utm_source=ts_nl&utm_medium=email&utm_email=0C810E7AE4E7C3CEB3816076F6F9881B&utm_campaign=reco_68354

“But if you were to look at unvaccinated 70-year-olds and compare them to vaccinated 70-year-olds, the vaccinated cohort has way lower rates of infection, hospitalization and death,” he said.

This suggests the vaccine is having a huge effect, but we would need to know the proportion of people vaccinated in each age group among those hospitalized to unpack the full impact, Bogoch said.

If you just look at the overall number of vaccinated people in hospital, “you might miss the point,” he said. “It’s the proportion that matters.”

Ontario has not released the data we’d need to correct for age. In the meantime, Bogoch said, it’s safe to assume the vaccine is likely having an even stronger effect than the limited provincial vaccine data suggests.

Even so, Bogoch said: “There’s no way to look at that data and not see how protective those vaccines truly are. It’s painfully obvious.”

Ed Tubb is an assignment editor and a contributor focused on crime and justice for the Star. He is based in Toronto.  Kenyon Wallace is a Toronto-based investigative reporter for the Star.






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