Children face mask study Catalonia Spain (it's in my Brownstone op-ed) but a key study so look it: "Unravelling the Role of the Mandatory Use of Face Covering Masks for the Control of SARS-CoV-2

in Schools, 5 year olds (no mask) versus 6 year olds (with masks); mask mandates in schools were not associated with lower SARS-CoV-2 incidence or transmission, masks are ineffective for school kids

see Brownstone op-ed I wrote, see reference 98:

https://brownstone.org/articles/studies-and-articles-on-mask-ineffectiveness-and-harms/

Background: a retrospective population-based study among 599,314 children aged 3 to 11 years (Catalonia, Spain) attending preschool (3-5 years, without FCM mandate, no mask) and primary education (6-11 years, with FCM mandate, with mask) with the aim of calculating the incidence of SARS-CoV-2, secondary attack rates (SAR) and the effective reproductive number (R*) for each grade during the first trimester of the 2021-2022 academic year, and analysing the differences between 5-year-old, without FCM, and 6 year-old children, with FCM.

Researchers found that ‘SARS-CoV-2 incidence was significantly lower in preschool than in primary education, and an age-dependent trend was observed. Children aged 3 and 4 showed lower outcomes for all the analysed epidemiological variables, while children aged 11 had the higher values. Six-year-old children showed higher incidence than 5 year-olds (3·54% vs 3·1%; OR: 1·15 [95%CI: 1·08-1·22]) and slightly lower but not statistically significant SAR and R*: SAR were 4·36% in 6 year-old children, and 4·59% in 5 year-old (IRR: 0·96 [95%CI: 0·82-1·11]); and R* was 0·9 and 0·93 (OR: 0·96 [95%CI: 0·87-1·09]), respectively.’

Overall, face mask mandates in schools were not associated with lower SARS-CoV-2 incidence or transmission, suggesting that this intervention was not effective.

In other words, let me say it another way, use of face masks in children, young children is illogical, irrational, absurd, non-sensical, specious, baseless, unscientific, unsound, and even harmful.