COVID-19 is at least 5 times deadlier than flu for hospitalized patients

A patient in the ICU.
(Image credit: Shutterstock)

COVID-19 truly is more deadly than the flu — patients hospitalized with COVID-19 were five times more likely to die than those with the flu, according to a new study from the Centers for Disease Control and Prevention (CDC). 

What's more, the study found COVID-19 patients were at higher risk for 17 additional, serious health complications, including pneumonia, respiratory failure and blood clots, compared with flu patients. However, because the study only looked at hospitalized patients, it can't directly compare overall mortality rates between the two diseases.

Ever since the new coronavirus was discovered in early January, people have compared it with the flu. As recently as this month, President Donald Trump drew criticism when he posted on Twitter that COVID-19 is "far less lethal" than the flu; the post was quickly flagged for spreading misinformation about COVID-19, according to NBC News.

Mounting evidence shows that COVID-19 is more severe than flu.

In the new study, published Tuesday (Oct. 20) in the CDC journal Morbidity and Mortality Weekly Report, the researchers compared complications from COVID-19 and flu using data from Veterans Health Administration hospitals nationwide. The authors analyzed information from nearly 4,000 patients — with an average age of 70 — hospitalized with COVID-19 from March 1 through May 31 2020, and more than 5,400 patients — average age of 69 — hospitalized with flu from Oct. 1, 2018 through Feb. 1, 2020.

Overall, 21% of COVID-19 patients died while hospitalized, compared with only 4% of flu patients — a more than five-fold difference. In addition, COVID-19 patients had more than double the risk of being admitted to the intensive care unit (ICU), and their length of stay was nearly three times as long. But these numbers take into account only those who were hospitalized. 

But evidence suggests a greater fraction of people who are infected with COVID-19 will need hospitalization than those who contract the flu, so COVID-19 is likelier more than five times deadlier than flu in the population overall. According to estimates from the CDC, about 1% of people who got sick with the flu were hospitalized during the 2019-2020 season. In contrast, up to 20% of COVID-19 patients may require hospitalization, according to early estimates from the World Health Organization.   

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COVID-19 patients were also at higher risk for dozens of complications. For example, compared with flu patients, COVID-19 patients were nearly 19 times more likely to develop acute respiratory distress syndrome (ARDS), a serious lung condition that causes low blood oxygen levels. COVID-19 patients were also more than twice as likely to develop  myocarditis (inflammation of the heart muscle), deep vein thrombosis (a blood clot typically in the legs), pulmonary embolism (a blood clot in the lungs) and intracranial hemorrhage (a brain bleed), than flu patients.

The study also found that minority groups, including Black and Hispanic patients, were at higher risk for many complications, such as respiratory, neurologic, and kidney complications, compared with white patients, even after the researchers took into account patients' age and underlying medical conditions. The finding adds to a growing body of evidence showing that minority groups have been hit hard by COVID-19, which may be due to "social, environmental, economic and structural inequities," the report said.

Overall, the findings "illustrate the increased risk for complications involving multiple organ systems among patients with COVID-19 compared with those with influenza," the authors wrote. "Clinicians should be vigilant for symptoms and signs of a spectrum of complications among hospitalized patients with COVID-19 so that interventions can be instituted to improve outcomes and reduce long-term disability."

Originally published on Live Science.  

Rachael Rettner

Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.