The burden of infectious diseases is felt mainly because of their dissemination in a short span of time resulting in epidemics or outbreaks. Globally, lower respiratory tract infections ranked as the fourth leading cause of death in 2012 and are the most significant infectious causes of death in the world. Influenza is an acute and highly contagious viral respiratory infection causing significant morbidity and mortality with worldwide public health implications. Seasonal influenza viruses continually circulate in yearly epidemics, while anti-genically novel strains, similar to the re-assorted pandemic H1N1 (pH1N1), emerge sporadically. The pH1N1 virus rapidly travelled around the world. As of June 9, 2009, a total of 73 countries had reported more than 26,000 laboratory-confirmed cases, and the World Health Organization (WHO) declared that the situation met the criteria for a phase 6 pandemic. By the time the pandemic had waned in August 2010, virtually all countries had reported laboratory-confirmed cases. While exact figures of the death toll from pH1N1 are unknown, estimates range from 105,700 to 395,600 deaths. The WHO provided early recommendations on administering vaccine to target groups and valuable field assistance to affected countries. WHO efficiently distributed more than 3 million courses of antiviral drugs to 72 countries.