The Protective Effect of Mask Wearing Against Respiratory Tract Infections

In this trial the researchers plan to recruit 4,000 volunteers to be randomly allocated either wearing face masks in public spaces where they are close to other people, or not wear face masks in such circumstances. For each participant the trial period is 2 weeks, after which they will be asked to complete a brief questionnaire which includes questions about whether they experienced the common cold, influenzas or COVID-19 symptoms during the trail period.