"Although officials may say that SARS-CoV-2 [the virus that causes COVID-19] is 'just another flu,' this is not true," the authors, from Harvard Medical School and Emory University
School of Medicine, wrote in their paper, published today (May 14) in the journal JAMA Internal Medicine.
Ever since the new coronavirus was discovered in early January, people have compared it with the flu, pointing out that influenza causes tens of thousands of deaths every year in the U.S. alone. Indeed, during the current flu season, the Centers for Disease Control and Prevention (CDC) estimates that there were up to 62,000 flu deaths in the U.S. from October 2019 through April 2020.
At a glance, this may appear similar to the toll of COVID-19, which as of early May, had caused about 65,000 U.S. deaths. (As of Thursday, May 13, the number of COVID-19 deaths in the U.S. was more than 82,000, according to Johns Hopkins University.)
But this doesn't match what health care providers are seeing on the frontlines of the pandemic, particularly in hot zones (such as New York City), "where ventilators have been in short supply and many hospitals have been stretched beyond their limits," the authors said.
This comparison is flawed because the CDC estimates of flu deaths are just that — estimates rather than raw numbers. The CDC does not know the exact number of people who become sick with or die from the flu each year in the U.S. Rather, this number is estimated based on data collected on flu hospitalizations through surveillance in 13 states.On the other hand, reported COVID-19 deaths are actual counts of people who died from COVID-19, not estimates. In other words, comparing estimates of flu deaths with raw counts of COVID-19 deaths is like comparing "apples to oranges," the authors said.
So for the new study, the researchers looked at actual counts of flu deaths per week, and compared those with counts of COVID-19 deaths.
Based on data from death certificates, during the deadliest week of flu season over the last several years, the counted number of U.S. deaths due to flu ranged from 351 during the 2015 to 2016 flu season to 1,626 during the 2017 to 2018 flu season, the authors said. The average number of flu deaths during the week of peak flu mortality in recent seasons (from 2013 to 2020) was 752 deaths.
In contrast, for COVID-19, there were 15,455 deaths reported in the U.S. during the week ending April 21 (the highest weekly death toll during the pandemic so far) the authors said
That means that the number of COVID-19 deaths for the week ending April 21 was about 10- to 40-fold higher than the number of influenza deaths for the most lethal week of the past seven flu seasons. That peak COVID-19 weekly death count is about 20 times higher than the average weekly peak flu death count, the authors said.
The authors note that their analysis has some limitations, including that the number of COVID-19 deaths may be undercounted because of limitations with testing for SARS-CoV-2 and false-negative test results. In addition, the authors point out that adult flu deaths are not required to be reported to public health authorities in the way that COVID-19 deaths are, potentially undercounting flu deaths as well.
Still, "our analysis suggests that comparisons between SARS-CoV-2 mortality and seasonal influenza mortality must be made using an apples-to-apples comparison, not an apples-to-oranges comparison," the authors concluded. "Doing so better demonstrates the true threat to public health from COVID-19."