Effect of Wearing a Face Mask on Hand-to-Face Contact by Children in a Simulated School Environment
Authors: Science Michelle , Caldeira-Kulbakas Monica , Parekh Rulan S. , Maguire Bryan R. , Carroll Stacie , Anthony Samantha J. , Bitnun Ari , Bourns Laura E. , Campbell Douglas M. , Cohen Eyal , Dodds Alison , Dubey Vinita , Friedman Jeremy N. , Greenwood Jodi L. , Hopkins Jessica P. , Imgrund Ryan , Korczak Daphne J. , Looi Thomas , Louca Emily , Mertz Dominik , Nashid John , Panzera Giovanna , Schneiderman Jane E. , Schwartz Kevin L. , Streitenberger Laurie , Vuppal Sunayna , Walsh Catharine M. , Jüni Peter , Matava Clyde T. ,   Back-to-School COVID-19 School Study Group, Allen Upton , Alvares Allison D. , Birken Catherine S. , Brown Ahuva , Carbone Vanessa L. , Christie Anne , Cividino Maureen E. , Cohen-Silver Justine H. , Cohn Ronald D. , Crosbie Jennifer , da Costa Bruno R. , Dharmaraj Blossom , Freeman Sloane J. , Gaebe Karolina , Hajjaj Omar , Huang Lennox , Khan Sarah , Lee Eon , Logeman Charlotte , Manteghi Sanaz , Moore Clara , Morris Shaun K. , Orkin Julia , Pelger Sydney D. , Pickel Lauren , Salman Soha , Shouldice Ainslie , Solomon Rachel , Thampi Nisha , Thorpe Kevin , Wasiak Anna , Xie Jiayin 
Published: October 2022

ImportanceWearing a face mask in school can reduce SARS-CoV-2 transmission but it may also lead to increased hand-to-face contact, which in turn could increase infection risk through self-inoculation.ObjectiveTo evaluate the effect of wearing a face mask on hand-to-face contact by children while at school.Design, Setting, and ParticipantsThis prospective randomized clinical trial randomized students from junior kindergarten to grade 12 at 2 schools in Toronto, Ontario, Canada, during August 2020 in a 1:1 ratio to either a mask or control class during a 2-day school simulation. Classes were video recorded from 4 angles to accurately capture outcomes.InterventionsParticipants in the mask arm were instructed to bring their own mask and wear it at all times. Students assigned to control classes were not required to mask at any time (grade 4 and lower) or in the classroom where physical distancing could be maintained (grade 5 and up).Main Outcomes and MeasuresThe primary outcome was the number of hand-to-face contacts per student per hour on day 2 of the simulation. Secondary outcomes included hand-to-mucosa contacts and hand-to-nonmucosa contacts. A mixed Poisson regression model was used to derive rate ratios (RRs), adjusted for age and sex with a random intercept for class with bootstrapped 95% CIs.ResultsA total of 174 students underwent randomization and 171 students (mask group, 50.6% male; control group, 52.4% male) attended school on day 2. The rate of hand-to-face contacts did not differ significantly between the mask and the control groups (88.2 vs 88.7 events per student per hour; RR, 1.00; 95% CI, 0.78-1.28; P = &amp;gt;.99). When compared with the control group, the rate of hand-to-mucosa contacts was significantly lower in the mask group (RR, 0.12; 95% CI, 0.07-0.21), while the rate of hand-to-nonmucosa contacts was higher (RR, 1.40; 95% CI, 1.08-1.82).Conclusions and RelevanceIn this clinical trial of simulated school attendance, hand-to-face contacts did not differ among students required to wear face masks vs students not required to wear face masks; however, hand-to-mucosa contracts were lower in the face mask group. This suggests that mask wearing is unlikely to increase infection risk through self-inoculation.Trial RegistrationClinicalTrials.gov Identifier: NCT04531254