The annual Hajj, or pilgrimage to Mecca, Saudi Arabia, is among the largest mass gatherings in the world draws about 2 to 4 million Muslim pilgrims every year; at least 1.5 to 2 million pilgrims are foreign visitors. This event is happening this week.

For observant Muslims, the Hajj is a religious duty and important act of faith. For public officials in Saudi Arabia and internationally, the Hajj poses serious challenges in the prevention and control of infectious diseases.

Applied epidemiologist at Metabiota, Jaclyn Guerrero, MPH joined me discuss several issues surrounding the Hajj and infectious diseases.