Same happened to us just before the school holidays. Daughter got sick from school and it spread to the wife and baby. They both had their flu jabs too. I had some very mild symptoms luckily.
It seems like everyone forgot the hygiene practices that covid had hammered in the last couple of years. Had to remind my daughter to stop kissing the baby
Between the 3 of us in my household it's been a solid 6 weeks of trading colds/sickness. On top of all the jabs etc. but daycare is just brutal for bringing bugs home.
I got covid just before Christmas last year and every time I've been ill since it's hit me a lot harder than I expected. I don't know if that's a sign of long covid but since the boffins keep pointing out different things the virus is responsible for, I'm gonna go ahead and assume that it's altered everyone's immune systems so that regular bugs are now kick-your-ass bugs.