The Scientific Pandemic Influenza Subgroup on Modelling (SPI-M) Summary

The purpose of this paper is to summarise the results of epidemiological modelling on Pandemic Influenza and their implications for policy. The view presented in this paper represents a consensus agreed by the SPI subgroup on modelling. The paper is regularly updated on the basis of new results. The focus of this paper is on the modelling results for significant pandemics, of which there were three in the twentieth century: 1918-19, 1957-58, and 1968-69. Such significant pandemics result in a relatively large number of people becoming clinically ill, suffering complications, requiring hospitalisation, and dying. The more recent H1N1 2009 pandemic was less significant, being, by nearly all measures, of considerably lower impact. The policy importance of the 2009 outbreak was as an exemplar of an event, which, at least in its early development is difficult to distinguish from a significant epidemic similar to the three 20th Century events with currently available sources of information