Not methodologically optimal but good enough shows masks are useless; kids < 5 to kids > 6 in Catalonia, Spain A Quasi-Experimental Study Nested in a Population-Based Cohort

Bottom line again, masks are useless for COVID; mask mandates in schools were not associated with lower SARS-CoV-2 incidence or transmission, suggesting that this intervention was not effective. 

Unravelling the Role of the Mandatory Use of Face Covering Masks for the Control of SARS-CoV-2 in Schools: A Quasi-Experimental Study Nested in a Population-Based Cohort in Catalonia (Spain)

FCM=facial mask covering

“a retrospective population-based study among 599,314 children aged 3 to 11 years attending preschool (3-5 years, without FCM mandate) and primary education (6-11 years, with FCM mandate)…

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…

Interpretation: FCM mandates in schools were not associated with lower SARS-CoV-2 incidence or transmission, suggesting that this intervention was not effective. Instead, age-dependency was the most important factor in explaining the transmission risk for children attending school.”