Yugo Shobugawa, Seth Wiafe, Saito Reiko, Hassan Zaraket, Inaida Shinako, Taniguchi Kiyosu, Suzuki Hiroshi: Prediction of Onset Time of Influenza : ( 6/2011 )
Epidemiology and Infection
Onset timing of influenza epidemics are not well defined and not predictable. To better define and predict the onset time of influenza epidemics, a weighted standard distance was calculated using surveillance data from 11.1 million national influenza-like illnesses generated from the 1999/2000 through 2008/2009 influenza seasons within Japan. In the current study, we demonstrated that the weekly weighted standard distance values, or the measure of spatial compactness of the distribution of reported influenza-like illnesses over a one-week time period, decreased to a minimal value before each seasonal epidemic peak.
Therefore, the lowest weighted standard distance value is a possible indicator for the onset of a nationwide influenza outbreak throughout Japan. This demonstration and definition are important for the analysis of influenza epidemics as well as the planning of preventive measures.