The Umrah is a pilgrimage to Mecca, Saudi Arabia, performed by Muslims that can be undertaken at any time of the year, in contrast to the Hajj.
The Hajj is an annual Islamic pilgrimage to Mecca, and a mandatory religious duty for Muslims that must be carried out at least once in their lifetime by all adult Muslims who are physically and financially capable of undertaking the journey.
Every year millions of Muslims of all ages, social, economic and regional backgrounds gather in Saudi Arabia for Hajj and Umrah. Such large human gatherings is a Public Health concern as pilgrims live, travel and pray in very close quarters, creating the ideal atmosphere for communicable diseases to spread and possibly mutate. These infections not only cause disease and death while performing mandatory religious duties but also cause epidemic globally, when pilgrims return to their native countries. As a result in a few months following Hajj and Umrah epidemics of hepatitis A, typhoid, flu and respiratory, eye, skin and other infections are observed all over the world.