Impact of Hajj on Global Health Security.

With the human society transfers from scattered pieces to a society as a whole and the advent of the aviation era, the occurrence of infectious diseases and their diffusion have led to international health security issues. As the world's largest and irrevocable annual transnational religious movement, the Hajj and its connection with health security concerns have caught attention since the ancient times, because a huge population from all over the world gathers in the holy city of Mecca, which has tropical arid climate. Currently, the international community and international organizations are implementing multilevel governance with respect to the health security issues of the Hajj. Relevant agencies include the World Health Organization and its regional branches, International Red Cross and Red Crescent Movement (ICRC), the Ministry of Hajj as well as the Ministry of Health of Saudi Arabia, and the public health sectors/agencies in various countries that are involved with Hajj activities. The international community has successfully held the Hajj events, even when facing the challenges brought by some viral respiratory diseases such as SARS and MERS. The Hajj has become a rare opportunity for all stakeholders to improve their capabilities in international health security governance.