ABSTRACT
Background Cost-effective interventions are needed to control the transmission of viral respiratory tract infections [RTIs] in mass gatherings. Facemasks are a promising preventive measure, however, previous studies on the efficacy of facemasks have been inconclusive. This study proposes a large-scale facemask trial during the Hajj pilgrimage in Saudi Arabiaandpresents this protocol to illustrate its feasibility and to promote both collaboration with other research groups and additional relevant studies. Methods/design A cluster-r and omised controlled trial is being conducted to test the efficacy of st and ard facemasks in preventing symptomatic and proven viral RTIs among pilgrims during the Hajj season in Mina, Mecca, Saudi Arabia. The trial will compare the 'supervised use of facemasks' versus 'st and ard measures' among pilgrims over several Hajj seasons. Cluster-r and omisation will be done by accommodation tents with a 1:1 ratio. For the intervention tents, free facemasks will be provided to be worn consistently for 7 days. Data on flu-like symptoms and mask use will be recorded in diaries. Nasal samples will be collected from symptomatic recruits and tested for nucleic acid of respiratory viruses. Data obtained from questionnaires, diaries and laboratory tests will be analysed to examine whether mask use significantly reduces the frequency of laboratory-confirmed respiratory viral infection and syndromic RTI as primary outcomes. Conclusions This trial will provide valuable evidence on the efficacy of st and ard facemask use in preventing viral respiratory tract infections at mass gatherings. This study is registered at the Australian New Zeal and Clinical Trials Registry [ANZCTR], ACTRN: ACTRN12613001018707 [http://www.anzctr.org.au]