This was a multistate, prospective, observational cohort of children and teachers attending in person schools in kindergarden through 12th grade where the school districs had the ability to perform contact tracing and determine primary vs secondary infections. During the study period (6/21-12/21) 46 districts had universal masking policies and 6 districts had optional masking policies.
Districts that optionally masked had 3.6x the rate of secondary transmission compared to universally masked school districts. Optionally masked districts had 26.4 cases of secondary transmission per 100 community acquired cases compared to only 7.3 cases in universally masked districts.
Bottom line: Universial masking was associated with reduced secondary transmission of SARS-CoV2 compared with optional masking policies.
References
Boutzoukas AE, Zimmerman KO, Inkelas M, et al. School Masking Policies and Secondary SARS-CoV-2 Transmission. Pediatrics. 2022;149 (6):e2022056687.
