It's not unusual for that age group even pre-panpanic. I remember a time period where at least one of my kids was sick every single winter without fail, sometimes multiple times (made coordinating excursions nigh on impossible and then we'd be stuck at home for stretches as J was working in the office and the kids were too young to leave home on their own in cases where it was just a cold).
They hardly ever get sick now.
I'm kind of vaguely concerned that the increased sanitisation that's been going on might have been detrimental for developing immune systems but like with everything else we'll see if it's actually a tihng somewhere down the line.