More people have died from Covid-19 than in the past 5 flu seasons combined. And coronavirus is much more contagious

(CNN) Once again, misleading comparisons between the flu and Covid-19 caught widespread attention across the internet.

"Flu season is coming up! Many people every year, sometimes over 100,000, and despite the Vaccine, die from the Flu," President Donald Trump tweeted. "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!!!"

That's not true. Covid-19 is more lethal than the seasonal flu.

Coronavirus

• The novel coronavirus has killed more than 210,700 people in the US in eight months, according to Johns Hopkins University.

• That's an average of more than 867 Covid-19 deaths a day in the US since the first known death on February 6.

The flu

• The flu killed an estimated 22,000 people in the US during the last flu season, according to the US Centers for Disease Control and Prevention. While the "exact timing and duration of flu seasons can vary," the CDC says, most cases happen between October and May.

• If 22,000 people died between October 1 and May 31, that would be an average of about 91 flu deaths a day over the span of eight months.

And in just eight months, Covid-19 has killed more people than the flu did during the last five flu seasons combined.

As for Trump's claim that the flu kills "sometimes over 100,000" people a year, CDC data from 1976 to 2007 and from 2010 until now show that's not even close.

There are several more reasons why Covid-19 is more dangerous than the flu -- and why extra precautions are needed:

Coronavirus is much more contagious than the flu

Research shows a person with the flu infects an average of about 1.28 other people.

But without mitigation efforts such as stay-at-home orders, a person with novel coronavirus infects an average of about 2 to 3 other people.

Coronavirus can be spread for many days without symptoms

With the flu, the incubation period is relatively short. People typically start feeling sick one to four days after infection, with symptoms often showing up within two days, the CDC says.

That means people who get sick from the flu will know they're sick fairly soon and will likely stay home, avoiding contact with others.

But the incubation period with coronavirus is about three to 14 days, and "symptoms typically appear within four or five days after exposure," according to Harvard Medical School.

"We know that a person with COVID-19 may be contagious 48 to 72 hours before starting to experience symptoms," Harvard experts write. "Emerging research suggests that people may actually be most likely to spread the virus to others during the 48 hours before they start to experience symptoms."

It's easy for asymptomatic carriers to infect others, said Anne Rimoin, an epidemiology professor at UCLA's School of Public Health.

"When you speak, sometimes you'll spit a little bit," she said. "You'll rub your nose. You'll touch your mouth. You'll rub your eyes. And then you'll touch other surfaces, and then you will be spreading virus if you are infected and shedding asymptomatically."

You can get a flu vaccine but not a coronavirus vaccine

Experts say the number of flu deaths could be drastically reduced if more people got flu shots. Even if you get a flu vaccine and later catch the flu, the symptoms are usually less severe.

Yet about half of Americans don't get vaccinated, including most children who die from the flu.

But with coronavirus, there's no publicly available vaccine yet. So the best ways to control the spread (while improving the economy) is with personal responsibility -- staying at least 6 feet away from those you don't live with, washing your hands frequently and wearing a face mask.