So when Webby says he's recommending family and friends get their flu shots earlier than usual this year, it's worth paying attention.

"Maybe this year it's a better idea to go out, get it earlier rather than later," Webby told Insider, adding that he's planning to get his own shot "very, very early in October." .

It's still impossible to know exactly what's going to happen during the US flu season this year, and when you might be most vulnerable to infection, but Webby said there are at least two clear reasons why he's getting his own shot imminently, rather than waiting several more weeks.

Florian Krammer, a virologist at Mount Sinai in New York, says he's going to do what he does every year and get his flu shot in late November, unless flu activity picks up dramatically where he lives before then.

So it's sort of that battle between getting it too early, or too late."