Influenza pandemics of 1918 and 2009: a comparative account

Abstract

The 2009 influenza pandemic A(H1N1)pdm09 of swine origin and the continued circulation of highly pathogenic avian H5N1 strain in humans are stark reminders of the unpredictable nature of the influenza virus. Experiences from the 1918 and 20th century influenza pandemics helped immensely in the preparation of a better response for A(H1N1)pdm09. The explosive pattern of the 1918 pandemic makes it a benchmark for pandemic planning and preparedness today. Its similarities with the 2009 pandemic makes it even more intriguing, and it is a great surprise that the two strains, separated by a period of 91 years, share such similar features. This review is an attempt to summarize the literature describing the important features of the 1918 and 2009 pandemics. This may provide a better understanding for the early detection and control of influenza pandemics in the future.