Washington, DC (CNN) While holding a press conference on Friday in Atlanta about the current coronavirus outbreak, President Donald Trump said that he didn't know people died of the flu. His grandfather died of influenza in 1918, according to Trump biographer Gwenda Blair.

"When I was hearing the amount of people that died with the flu, I was shocked to hear it," Trump said while touring the Centers for Disease Control and Prevention's headquarters. "Over the last, long period of time when people have the flu, you have an average of 36,000 people dying. I've never heard those numbers, I would've been shocked. I would have said, 'Does anybody die of the flu?' I didn't know people died from the flu."

Trump is right that tens of thousands of Americans die each season from the flu. The CDC estimates that there were more than 34,000 deaths from the flu in the 2018-2019 flu season. The previous season that number was estimated to be more than 61,000.

In 1918, an influenza pandemic spread throughout the world and killed an estimated 675,000 people in America and 50 million worldwide, according to the CDC . Trump's paternal grandfather, Friedrich Trump, was one of those people who died of the influenza in 1918, according to Blair's book, "The Trumps: Three Generations of Builders and a President," which was first published under a different title in 2001 and later republished after Trump won the White House. The Washington Post was the first outlet to point out, in the wake of Trump's comments last week, that the flu killed his grandfather.

CNN spoke to Blair about Trump and his family history on Sunday. Blair, who hasn't spoken to Trump in over a decade, suggested it was unlikely the President didn't know how his grandfather died.

Trump is aware of some detail's of his grandfather's life. In a 2016 documentary, "The Kings of Kallstadt," Trump mentioned his family's first landing in America. "My grandfather Friedrich Trump came to the United States in 1885," Trump said in the documentary. "He joined the great gold rush, he did fantastically well, he loved this country."

At the time of his death in 1918, Friedrich was a 49-year-old businessman with three kids living in Queens, Blair writes in her book.

Blair recalled that when she interviewed Trump, he didn't show much interest in his own family history, preferring instead to focus on his business.

The White House has not responded to request for comment, nor has it answered questions from CNN about whether the President knew his grandfather died from the flu.

The following interview with Blair has been edited and condensed for clarity and length:

CNN: When visiting the CDC on Friday, the President said he was shocked to hear about the number of people who have died from the flu. But as you've noted in your book, his grandfather, Friedrich Trump, died in the flu pandemic of 1918. What are your thoughts on that?

Blair: He is not a student of history. He's only looking forward. He has no rearview mirror and that means he learns little. There's that old cliche about people who don't learn from history are bound to repeat it, and I think that's what he's currently in the middle of re-enacting.

Can you explain that a little more?

Oh well, certainly, specifically, with regard to health crises, and then more broadly his refusal to engage, learn from experts in all manner of fields. And this is yet another example of that -- his refusal to actually learn about how epidemics start, how to confront them, the kinds of planning that's necessary, the preparations that are necessary.

Has Trump mentioned his grandfather in the past? Do you know how much he knew of his grandfather?

When I interviewed him for my book, he was not very interested in history in general -- family history. He was interested in his own business career, that was 100% of his interests at the time I interviewed him. But he knew generally about his father, grandfather and his grandmother, who was a widow after her husband died in 1918. His grandmother, also a German immigrant, lived until the 1960s, across the street from the Trump family during much of Donald Trump's childhood and was around until he was in college and was very close to his father. So his grandmother was around. I mean not just around -- actively involved in the family.

But is it possible that Trump was not aware that his grandfather died from the flu?

Within the realm of possibility, sure. Within the realm of probability, no.

And why do you say that?

Well I wrote a book about it.

There were articles about it, there have been articles since then in which this was mentioned. I think his own father (Fred Trump) knew, as I described in my book. When he was 12, he was with his dad walking down the street in Queens, and his father pretty suddenly said, "I don't feel well, we have to go home." He died that day. And Fred Trump went on to tell me that it was so shocking and so sudden he didn't really understand what had happened. It was so sudden, but he saw that his mother -- that is to say Donald Trump's grandmother -- he saw his mother really grief-stricken because her husband had just died.

An uncle, his father's brother-in-law, also died during the pandemic in 1918.

Do you think President Trump and his grandfather share any similar traits?

Certainly business sharpness, shrewdness. His grandfather was a guy who pushed the envelope as far as he could.

There have been reports that the President is a "germaphobe." How do you think he's handling the coronavirus?

To date, he seems to be handling it the same way he handled everything else in his career, which was, insist he's right. If there are accusations, throw them back at whoever made the accusation. Double down whenever some new piece of evidence, information comes in to say even more forcefully that he was right. To look for ways to promote his own candidacy.

There's a pattern of how he behaves -- I believe the country has come to be very familiar with. But the coronavirus isn't a person. ... This isn't a rival or competitor, but it's being treated that way by Trump. And everything that I can see suggests that is a really bad strategy for dealing with an epidemic. Maybe it works politically, but an epidemic is a disease; it's not a political rival.