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
by Paul Alexander
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.