California

Of those reports that had numbers, I counted only 112 people
In the entire state participated in this protest.

I notice NPR provided very little in total numbers.

But this report actually did some well...reporting.

"On Monday afternoon, a district official told NBC 7 that the day's attendance rate —90.91% — was slightly less than last Monday's, when 92.36% of students were in class. There are more than 103,000 students in the district, according to San Diego Unified."

https://www.google.com/amp/s/www.nbcsandiego.com/news/local/parents-keep-kids-home-employees-call-out-to-protest-school-vaccine-mandate/2750004/%3famp

So one public school system had maybe a 1.45 percent participation rate in the protest. That's high because you have to assume no one was out sick, not likely in a pandemic.

So the protest was a complete bust.