Facemask against viral respiratory infections among Hajj pilgrims: A challenging cluster-randomized trial

Alfelali, Mohammad; Haworth, Elizabeth A.; Barasheed, Osamah; Badahdah, Al-Mamoon; Bokhary, Hamid; Tashani, Mohamed; Azeem, Mohammad I.; Kok, Jen; Taylor, Janette; Barnes, Elizabeth H.; El Bashir, Haitham; Khandaker, Gulam; Holmes, Edward C.; Dwyer, Dominic E.; Heron, Leon G.; Wilson, Godwin J.; Booy, Robert; Rashid, Harunor; on behalf of the Hajj Research Team

doi:10.1371/journal.pone.0240287

Facemask against viral respiratory infections among Hajj pilgrims: A challenging cluster-randomized trial

Background In this large-scale cluster-randomized controlled trial (cRCT) we sought to assess the effectiveness of facemasks against viral respiratory infections. Methods and results Over three consecutive Hajj seasons (2013, 2014, 2015) pilgrims’ tents in Makkah were allocated to ‘facemask’ or ‘…