Well, the new grandson had it. We got him Christmas Eve and his mother FAILED to tell us that he was sick.
I was first. Had a previously scheduled Doctors apt the day after Christmas. I felt fine, but on check-in was notified that I had a temp or 100.8 It got up to 101.... and I had about 1 day of symptoms... but recovered quickly and fully and wound up taking care of the baby boy, my 10 year old granddaughter AND my wife, who BTW, was sick for a FULL TWO WEEKS afterwards.
And yes; we share child care duties EQUALLY... in fact, for SOME reason none of us can figure out, the kids AND grandkids ALWAYS COME TO/PREFER ME for comfort. When they were/are sick, they come to pop, not nana. And when the want to be held, they come to me.
So I actually had MORE exposure to the lil boy than the wife did... but got well in a day while hers drug on.
And yes; we all had our flu shots. Mine from the Department, theirs from our HMO.