My oldest starting preschool was one of the worst times in my life. We were sick from august to december, then january to may. Dreadful.
It got better. My youngest is 3 now and is ahead of where my oldest was due to having 2 older siblings importing illnesses for several years, and this year we finally were mostly not sick all school year. Which is to say, we were probably closer to the 15 days "materially sick" mark. I say materially sick to mean, definitely sick, though perhaps not taken out of school (due to not technically being outside of the health exclusion policy, and sometimes I only realize they were "materially" sick after they got home instead of just "passably sick given kids will basically have a lingering cough from august to may).
I heard about vitamin D during covid, and that and hand sanitizer are the only 2 things we still do. I haven't been sick for a few years. Before covid (and vitamin D supplements), it was at least 25 days sick every year, if not more.
This sounds roughly normal for what I came to expect back when I worked in an office with many people who had school-age kids. I had a colleague who wryly referred to his kids as "my little plague carriers".
When I stopped working in an office, I almost completely stopped getting sick.
+1 for office work as disease source.
Plus taking public transport (mostly underground trains). Today I avoid the subway almost completely, taking my bike almost everywhere, to avoid getting sick during winter.
(No kids though)
I've had years in which most people in my immediate surroundings were sick for weeks or months (likely exacerbated by mold, school, and travel). Also years in which I never really got sick at all.
Healthy lifestyle and food have a huge part. I date teachers a lot, and I've taken several people from constantly sick to almost never sick for 1+ year by just changing food and not going out to bars. I know this sounds like a random flippant comment, but I've done it enough times and consistently enough that I have no doubt personally.
For my family of 5 w/ school age children I would say that is a pretty reasonable estimate, maybe even a bit low for us. There are levels of “sick” though and I would say for us most respiratory illnesses are very mild and are a minor annoyance. Where it becomes more menacing is when we have sick kids and sick parents at the same time.
This seems completely unbelievable to me. Totally outside of my personal, professional, and family experience.