Alfelali M, Barasheed O, Koul P, Badahdah AM, Bokhary H, Tashani M, Bakarman M, Khandaker G, Booy R, Rashid H Abstract Hajj and mass gatherings Influenza 2019 Expert Review of Vaccines 2019;18:1103-1114. doi: 10.1080/14760584.2019.1646130