Influenza virus but not MERS coronavirus circulation in Iran, 2013-2016: Comparison between pilgrims and general population.

Background: The pilgrimage to Mecca and Karbala bring many Muslims to a confined area. Respiratory tract infections are the most common diseases transmitted during mass gatherings in Hajj, Umrah and Karbala. The aim of this study was to determine and compare the prevalence of Middle East respiratory syndrome coronavirus (MERS-CoV) and influenza virus infections among Iranian general population and pilgrims with severe acute respiratory infections (SARI) returning from Mecca and Karbala during 2013-2016.