Understanding and addressing the obstacles to a trial of face masks in schools: a mixed-methods feasibility study

BACKGROUND: Face masks are a commonly used public health measure to control the spread of airborne infections, including in school-aged children. However, no trial of their effectiveness has been conducted in school settings to date. We undertook a mixed-method study to explore the feasibility of conducting such a trial. METHODS: This study followed a multi-phased mixed-methods approach. We first conducted a secondary analysis of qualitative data (39 young people) and five Patient and Public Involvement focus groups (11 young people, three teachers, two parents), to understand the barriers and facilitators relating to engaging with a trial of face masks. Strategies to enhance recruitment and engagement were generated based on this qualitative work. These were refined further in additional PPI focus groups with young people (n = 7). We then conducted a 6-week two-arm parallel cluster-randomised feasibility trial in a local school. Two year groups were cluster-randomised into one of the two arms: (1) school rules group (SR, control), following school policy at the time on the use of face coverings; (2) face-mask group (FM, intervention), wearing standard lightweight surgical masks while in an indoor setting for the duration of the school day. Primary outcomes were recruitment and adherence to trial procedures: completion of surveys capturing frequency of mask-wearing, impact of mask-wearing, mood and compliance with the provision of weekly saliva samples for the detection of viral infections. RESULTS: A total of 93 pupils (29% of approached) participated in the feasibility trial and were randomised (SR = 46, FM = 47). The number of intervention participants wearing face masks at all times while at school increased from 7% at baseline to an average of 28% over trial weeks 1-5. Completion rate of weekly surveys varied between 15 and 100%, while provision of weekly saliva samples varied between 15 and 38% over the trial period. CONCLUSION: Recruitment and adherence in the trial were lower than those observed in trials conducted in other community or healthcare settings. Our data suggest that incentivising participants, giving participants greater agency in how to fulfil trial procedures such as giving them choices on where to collect saliva samples, and allowing survey completion during timetabled activities would be important considerations for a future trial.