Alfelali M, Barasheed O, Badahdah AM, Bokhary H, Azeem MI, Habeebullah T, Bakarman M, Asghar A, Booy R, Rashid H, Hajj Research Team Abstract Hajj and mass gatherings Influenza 2018 Vaccine 2018;36:2112-18. doi: 10.1016/j.vaccine.2018.03.007