Coronavirus kills 20 times more Americans than flu, say experts who warn comparing the two can be dangerous

The national rate of death among people infected with coronavirus and who show symptoms is 1.3%, a study found. The comparable rate of death for the seasonal flu is 0.1%


                            Coronavirus kills 20 times more Americans than flu, say experts who warn comparing the two can be dangerous
(Getty Images)

The new coronavirus could be killing 20 times more people in the US each week on an average than the flu at its peak, say scientists. Based on their findings, researchers from Harvard Medical School, Boston, and Emory University School of Medicine, Atlanta, say that while officials may say that SARS-CoV-2, the virus that causes Covid-19, is "just another flu", that is not true.

The research team found that during the week ending April 21, 2020, 15,455 Covid-19 counted deaths were reported in the US. The reported number of counted deaths from the previous week, ending April 14, was 14,478. By contrast, according to the US Centers for Disease Control and Prevention (CDC), counted deaths during the peak week of the influenza seasons from 2013-2014 to 2019-2020 ranged from 351 (2015-2016, week 11 of 2016) to 1,626 (2017-2018, week three of 2018). 

"The mean number of counted deaths during the peak week of influenza seasons from 2013-2020 was 752.4 (ranging between 558.8-946.1). These statistics on counted deaths suggest that the number of Covid-19 deaths for the week ending April 21 was 9.5-fold to 44.1-fold greater than the peak week of counted influenza deaths during the past influenza seasons in the US, with a 20.5-fold mean increase (ranging between 16.3-27.7)," says the study published in JAMA Internal Medicine.

Since the new coronavirus first emerged, people have compared it with the flu, pointing out that influenza causes tens of thousands of deaths every year in the US alone. Data shows that as of early May 2020, approximately 65,000 people in the US had died of Covid-19. This number appears to be similar to the estimated number of seasonal influenza deaths reported annually by the CDC. The agency estimates that there were 24,000-62,000 flu deaths in the US from October 1, 2019, through April 4, 2020.

However, this does not match frontline clinical conditions, especially in some hotspots of the coronavirus pandemic where ventilators have been in short supply and many hospitals have been stretched beyond their limits, says the research team. They explain that the demand for hospital resources during the Covid-19 pandemic has not occurred before in the US, even during the worst of influenza seasons. "Yet public officials continue to draw comparisons between seasonal influenza and SARS-CoV-2 mortality, often in an attempt to minimize the effects of the unfolding pandemic," they say.

According to experts, the demand on hospital resources during the Covid-19 pandemic has not occurred before in the US, even during the worst of influenza seasons (Getty Images)

The root of such incorrect comparisons may be a knowledge gap regarding how seasonal influenza and Covid-19 data are publicly reported, says the team. Researchers explain the comparison between Covid-19 and flu is flawed because the CDC estimates of flu deaths are just that — estimates rather than raw numbers. The CDC, like many similar disease control agencies around the world, presents seasonal influenza morbidity and mortality not as raw counts but as calculated estimates based on data collected on flu hospitalizations through surveillance.

For example, between 2013-2014 and 2018-2019, the reported yearly estimated influenza deaths ranged from 23,000 to 61,000. Over that same period, however, the number of counted influenza deaths was between 3,448 and 15,620 yearly. On an average, the CDC estimates of deaths attributed to influenza were nearly six times greater than its reported counted numbers. Conversely, Covid-19 deaths are at present being counted and reported directly, and not estimated. “As a result, the more valid comparison would be to compare weekly counts of Covid-19 deaths to weekly counts of seasonal influenza deaths,” says the study.

"In summary, 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. Doing so better demonstrates the true threat to public health from Covid-19," say researchers. The team says that deaths from Covid-19 may be undercounted owing to ongoing limitations of test capacity or false-negative test results. When patients present late in the course of illness, upper respiratory tract samples are less likely to yield positive test results," they add. 

According to experts, case fatality rates are a topic of confusion. Comparisons of the case fatality rates of SARS-CoV-2 and influenza are premature, they say. Estimates of case fatality rates for Covid-19 range from less than 1% in some nations to approximately 15% in others. "This wide range reflects limitations in calculating case fatality rates. These include failure to account for scarcity in testing (thereby falsely decreasing the denominator) and incomplete follow-up information for people who were critically ill but still alive when last assessed (thereby decreasing the numerator). Eventually, results from serologic studies will help to determine a more accurate denominator for the case fatality rate of SARS-CoV-2," says the team.

Deaths from Covid-19 may be undercounted owing to ongoing limitations of test capacity or false-negative test results (Getty Images)

Based on the analysis, the team cautions that directly comparing data for two different diseases when mortality statistics are obtained by different methods provides inaccurate information. Moreover, the repeated failure of government officials and others in society to consider these statistical distinctions threatens public health, say experts. Government officials may rely on such comparisons, thus misinterpreting the CDC’s data, when they seek to reopen the economy and de-escalate mitigation strategies, warns the team. 

Covid-19 deadlier than flu, says analysis

Another study by researchers from the University of Washington concludes that Covid-19 is a lot more deadly than the flu. The national rate of death among people infected with the novel coronavirus and who show symptoms is 1.3%, the study found. The comparable rate of death for the seasonal flu is 0.1%. In the state of Washington, for example, the county-specific fatality estimates ranged from 0.5% to 3.6%. King County at 3.6% is the highest among all 116 US counties studied.

Among the state's other counties that could be included in this analysis was Chelan County at 2.3%, Island County at 2.2%, and Spokane County at 2%, according to the analysis published in Health Affairs. A conservative estimate of 20% of the US population becoming infected by the end of the year — with the current trends in social distancing and healthcare supply continuing while accounting for those infected who will recover asymptomatically -- could result in the number of deaths climbing to between 350,000 and 1.2 million, say experts.

This is a staggering number, which can only be brought down with sound public health measures, experts caution. As of May 20, more than 1,528,560 coronavirus cases and over 91,920 deaths have been reported from across the US, according to the Johns Hopkins tracker.

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