“COVID is just a big flu,” says your brother-in-law or your sister-in-law who refuses to be vaccinated? No. Truly not. Despite all the health measures in force since March 2020, COVID-19 has killed on average 12 times more deaths per day than the flu usually does in Quebec.
Since the start of the pandemic, there have been an average of 17.7 deaths per day linked to COVID-19, compared to 1.5 deaths per day linked to influenza in the pre-COVID years (average for years 2016 to 2018 , on an annual basis; see notes).
The severity of the flu – its official name: influenza – varies from year to year. In 2016, the flu caused relatively few deaths, at 213. In 2018, the flu was very virulent, killing 1,044 people. It was the most virulent flu of the past decade.
But the severity of COVID-19 is beyond measure: it caused 8,479 deaths in 2020 (the year when Quebec was not vaccinated) and 3,075 deaths in 2021. The ratio of deaths per day is six times higher for the COVID-19 than for the 2018 flu.
With a vaccination rate of 89% among those 12 years and older, COVID-19 claims far fewer lives during the fourth wave. Since July 18, there have been 2.3 deaths per day linked to COVID-19. These figures, however, underestimate the dangerousness of COVID-19, because the number of deaths linked to COVID-19 is lower in summer than in winter, and the fourth wave barely enters in the winter period. By way of comparison, influenza does not cause hospitalizations (or deaths) between April and early December.
“COVID is in a class of its own,” says virologist Benoit Barbeau, professor at UQAM. The flu lasts only six months, from November to April. Most deaths occur in December, January and February. Deaths from COVID-19 slow in the spring and summer, but the virus is transmitted year round, unlike the flu virus. The influenza virus and the SARS-CoV-2 that causes COVID-19 belong to two different families of viruses. SARS-CoV-2 is more virulent and about four times more transmissible (for the Delta variant) than the influenza virus.
Much more likely to be hospitalized
COVID-19 sends many more people to hospital than the flu. In 2021, COVID-19 resulted in three times more hospitalizations (11,141) than the flu usually does (average of 3,269 hospitalizations per year). When admitted to hospital, patients suffering from COVID-19 are twice as likely to be admitted to intensive care.
During the first wave, the rate of hospitalized patients for COVID-19 who died was about six times higher than for influenza (for previous years), according to a study by the National Institute of Public Health of Quebec ( INSPQ). This rate “has, however, decreased since the first wave [de la COVID-19], because we have learned how to better manage hospitalized patients, ”says Dr.D Rodica Gilca, specialist in public health and medical consultant at the INSPQ.
Unprecedented health measures
COVID-19 has claimed an average of 12 times more lives in Quebec than the flu … while Quebec, like the rest of the world, has deployed unprecedented health measures to slow the transmission of the virus, which is much more transmissible than the flu .
On average, one person with influenza infects another person (reproduction rate of 1), while a person with the Delta variant who does not isolate themselves infects five others (reproduction rate of 5).
Without these health measures, the number of deaths linked to COVID-19 would likely have exploded. Thanks to them, only 15% of Quebecers have contracted COVID-19 since February 2020. (The number of official cases represents 5% of Quebecers, but experts believe that this figure must be multiplied by three to count all non-cases. detected.)
In the pre-COVID years, what percentage of Quebecers caught the flu? Difficult to say, because there is no official data. In the United States, it is estimated to be between 3% and 14% of the population. “It depends on the years, but influenza can affect between 5% and 20% of the population,” says Dr.D Rodica Gilca. Since the start of the pandemic, there has been no influenza, in particular due to health measures.
In Quebec, approximately 27% of the adult population was vaccinated against influenza in the pre-COVID-19 years, including 80% of residents in CHSLDs. But the influenza vaccine has limited effectiveness: the effectiveness rate varies between 30% and 60% depending on the year, depending on the DD Rodica Gilca. The COVID-19 vaccine is 90% to 95% effective against the risk of hospitalization. And Quebecers aged 12 and over are vaccinated in a proportion of 89%.
The long COVID
A small amount of coronavirus infections lead to a disease that can turn out to be dramatic: long-term COVID. Struggling with extreme fatigue, some people with long-term COVID are unable to lead normal lives. So far, very little is known about the long-term COVID.
Some milder symptoms may also persist for months after infection. “It is estimated that about a quarter of infected people, perhaps even a third, will have sequelae over several months, which is not the case for the flu,” says Alain Lamarre, virologist and professor at the National Institute for Scientific Research (INRS).
Age of death decreases for COVID
Throughout the pandemic, COVID-19 affects roughly the same age groups as the flu: so far, 91% of Quebecers who died from COVID were at least 70 years old. In comparison, 89% of deaths attributable to influenza affected this age group during the years 2016 to 2018.
The age of deaths, however, has declined significantly since the third wave of COVID-19 (since March 2021), because the coronavirus attacks more unvaccinated people who are younger. Unvaccinated people are 16 times more likely to be hospitalized and 20 times more likely to die from COVID-19 than people who are vaccinated. Since the start of the fourth wave, that is since July 18, 2021, the 70 years and over represent 71% of deaths.
Notes: We did not use influenza-related death data for the years 2019 (386 deaths) and 2020 (340 deaths), as these data are provisional. Almost 100% of influenza-related deaths in 2020 occurred before the onset of COVID-19, in early winter 2020. Unless otherwise noted, data used in this article (including tables) is as of December 9, 2021 for COVID-19 (death by date of death). To average a day for the flu, we counted every day of the year. By counting only the winter period for influenza and the whole year for COVID-19 (there are deaths attributable to COVID-19 all year round), we would arrive at an intensity of the daily death rate six times higher. higher for COVID-19 than for influenza.