Trump is still comparing COVID-19 to the flu. But the coronavirus has already killed 3 times more people than flu does in a year.

• President Trump tweeted on Tuesday that the coronavirus was "far less lethal" than the flu in most populations, adding that "sometimes over 100,000" people die from the flu.
• Both claims are false: The most Americans who have ever died from the flu in one season is 61,000. The coronavirus' death rate in the US is also far higher than the flu's.
• Facebook removed and Twitter flagged Trump's post for violating misinformation policies.

President Donald Trump hadn't even been back at the White House 24 hours following his hospitalization for COVID-19 when he brought back a tired comparison: He claimed the coronavirus was akin to the seasonal flu.

"Many people every year, sometimes over 100,000, and despite the Vaccine, die from the Flu," Trump tweeted on Tuesday morning. "Are we going to close down our Country? No, we have learned to live with it, just like we are learning to live with Covid, in most populations far less lethal!!!"

However, it's simply not true that 100,000 people die annually from the flu or that COVID-19 is less lethal than the flu. According to the Centers for Disease Control and Prevention, the US's worst flu season in the last decade — the 2017-2018 season — killed 61,099 Americans, while the coronavirus has already killed more than 210,000 people in the country.

Twitter flagged Trump's post within hours as "misleading and potentially harmful information." Facebook took the post down for violating its COVID-19 misinformation policy.

"This is not the flu — not even close. It's a much more serious illness without question," David Battinelli, chief medical officer at Northwell Health and a professor of medicine at Hofstra University, told Business Insider of COVID-19.

He added: "Trump should know that. I'm sure he has had the flu once or twice and didn't go to hospital. He got this and went in for two days."

The worst flu season in the last decade killed 61,000 Americans

Influenza is no cakewalk. Every year, the seasonal flu kills tens of thousands of Americans. Last year, there were more than 18 million flu-related medical visits and 405,000 hospitalizations.

But there has never been a season in which "over 100,000" Americans died of the flu. The average number of people who've died of flu each year in the US since 2010 is about 36,000, CDC data shows. Most recently, between 2019 and 2020, 21,909 people died.

Trump was well aware of that in March:

—Donald J. Trump (@realDonaldTrump) March 9, 2020

It's possible the president's latest tweet was referring to the annual global death toll from flu epidemics. According to the World Health Organization, between there are 290,000 and 650,000 respiratory deaths related to influenza worldwide every year.

But that's far lower than the global coronavirus death toll: More than 1 million people have died of COVID-19 since the start of the pandemic.

The coronavirus isn't 'far less lethal' than the flu

About 0.1% of people who got the flu died in the US last year, according to the CDC.

The US's current COVID-19 case-fatality rate, also known as its death rate, is 2.8%. The number comes from dividing the number of deaths by the number of total cases.

That's probably higher than the infection-mortality rate (IFR) — the overall proportion of people who die as a result of their coronavirus infection. Research suggests the IFR is significantly lower because that figure would include Americans whose infections are not reported because they have no symptoms, those who don't get tested, as well as those whose COVID-19 deaths aren't recorded.

"The studies I have any faith in are tending to converge around 0.5–1%," Timothy Russell, a mathematical epidemiologist at the London School of Hygiene and Tropical Medicine, told Nature in June. But that's still five to 10 times higher than the flu's IFR.

Plus, the infection-mortality rate in a given population depends on the age, demographics, and prevalence of preexisting health conditions in that group. The coronavirus disproportionately impacts Black Americans, people older than 65, and patients with preexisting health issues like heart disease.

The IFR of any illness tends to decrease over time as doctors get better at treating patients.

But even so, Trump's assertion that the coronavirus is "far less lethal" than the flu is off-base. In fact, the president seems to have known that the virus was worse than the flu when he talked to veteran journalist Bob Woodward about it during the winter.

Recordings of interviews between Trump and Woodward show that on February 7, Trump said to Woodward: "It goes through the air. That's always tougher than the touch. You don't have to touch things. Right? But the air, you just breathe the air and that's how it's passed. And so that's a very tricky one. That's a very delicate one. It's also more deadly than even your strenuous flus."

Nonetheless, Trump has repeatedly downplayed the severity of the pandemic to the public by likening the flu to COVID-19.

One reason Americans are less impacted by the flu than the coronavirus, of course, is that we have seasonal vaccines. Plus, doctors also have better treatment options.

"We've done much better with the flu because were vaccinating more people and we have antiviral drugs that are known to work," Battinelli said.

So it's possible that at some time in the future, COVID-19 will become less deadly. A coronavirus vaccine also isn't likely to be necessary every year the way flu shots are, because unlike the flu, the coronavirus does not mutate rapidly.