Canadian Study Reaffirms COVID-19 Far More Dangerous than Seasonal Flu

Canadian Study Reaffirms COVID-19 Far More Dangerous than Seasonal Flu

Recent research led by Canadian investigators find that COVID-19 is far more dangerous than the seasonal flu as measured by hospital deaths. In fact, the study results, published in the Canadian Medical Association Journal (CMAJ), reveals that the risk of death from COVID-19 for hospitalized patients was 3.5 times higher than from influenza.   The Canadian findings are similar to results reported in both France and the United States.

The Study

Titled “Characteristics and outcomes of hospital admissions for COVID-19 and influenza in the Toronto area,” this study compared hospitalizations for influenza between November 1, 2019, and June 30, 2020, in 7 large hospitals in Toronto and Mississauga — areas with large populations and high levels of COVID-19. It included all patients admitted to medical services or the intensive care unit (ICU) for influenza or COVID-19. There were 783 hospitalizations for influenza in 763 unique patients compared with 1027 hospitalizations for COVID-19 in 972 unique patients (representing 23.5% of all hospitalizations for COVID-19 in Ontario during the study period).

The Results

Most patients hospitalized with COVID-19 had few other illnesses, and 21% were younger than 50 years of age. People younger than 50 also accounted for almost 1 in 4 (24%) admissions to the ICU. Moreover, people hospitalized for COVID-19 had greater use of the ICU, were more likely to be put on a ventilator and had longer hospital stays than people with influenza.

Dr. Amol Verma, one of the researchers from St. Michael’s Hospital, Unity Health Toronto, and the University of Toronto, reported, “We can now say definitively that COVID-19 is much more severe than seasonal influenza.” Dr. Verma continued, “Patients admitted to hospital in Ontario with COVID-19 had 3.5 times greater risk of death, 1.5 times greater use of the ICU, and 1.5 times longer hospital stays than patients admitted with influenza.”

The Question of Age

Yes, the elderly are impacted severely by SARS-CoV-2 but the virus strikes all. COVID-19 is a scary disease. First the probability of a person over 75 dying in the hospital due to COVID-19 is at 40% according to this study. But adults under 50 were also materially impacted: during the first wave 20% of adults in this cohort were hospitalized due to COVID-19. And according to Dr. Verma, “Nearly 1 in 3 adults younger than 50 hospitalized with COVID-19 required intensive care, and nearly 1 in 10 required an unplanned readmission to the hospital after discharge.”

Function of Immunity?

Verma also suggested that the higher death rates for example could result from the fact that there are just lower levels of immunity due to the newness of this disease. The Toronto-based research suggested that perhaps with vaccinations, more treatments and more recovered patients that overall immunity will rise. But the curveball of variants of the virus raises concerns for greater severity to come.

Lead Research/Investigator

Amol Verma, MD, M.Phil 

Other authors listed in the study document.

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