One of those episodes was the 1958 pandemic, which killed 116,000 in the United States.
Another was 1918.
That is the year Trump's paternal grandfather died.
He died of the flu.
In 1918, Friedrich Trump was a successful, 49-year-old businessman, husband and father of three living in Queens, according to Gwenda Blair in her 2001 book "The Trumps: Three Generations That Built an Empire." One day in May, he came home from a stroll feeling sick. He died almost immediately.
He was a victim of the first wave of the Spanish flu pandemic. A second, deadlier wave hit in the fall. All told, the pandemic killed at least 50 million people worldwide and 675,000 in the United States, according to the CDC.
Friedrich's eldest son, Frederick, was only 12 when his father died, but he and his mother would pick up the family business. It would be another 28 years before Fred and his wife would have their fourth child, a boy they named Donald.
This same grandfather's biography has come up as a sticking point before. Friedrich came to the United States at 16 from Germany and today would be classed as an "unaccompanied alien child," experts told The Washington Post in 2018. Trump has come under fire for his administration's treatment of unaccompanied minors and other children from Central America trying to enter the country via the southern border.
In his 20s, Friedrich Trump made his way to the Pacific Northwest, where he made his fortune opening taverns, restaurants and hotels, usually in red-light districts, in Gold Rush-era mining towns.
He also attempted a return to Germany in his 30s but was deported because he had avoided the military draft as a teenager.
The president is at least partially aware of his grandfather's biography. As recently as February 2019, he said in a speech, "My grandfather was up in Alaska for a long time. He was looking for gold. He was searching for gold. He didn't find it, but he started opening up little hotels for those looking for gold. And it worked out."
At other times, he has said erroneously that his father, not his grandfather, was born in Germany. His father was born in New York.
At the same news conference Friday where Trump appeared unaware of his grandfather's cause of death, he cited another family member - a "super-genius uncle," his grandfather's youngest son - as having given him the family genes to understand the science of the coronavirus outbreak.
"People are really surprised I understand this stuff," he said. "Every one of these doctors said, 'How do you know so much about this?' Maybe I have a natural ability."
