講座內容：Past influenza pandemicsappear to be characterized by multiple waves of incidence, but the mechanismsthat account for this phenomenon remain unclear. We propose a simple epidemicmodel, which incorporates three factors that might contribute to the generationof multiple waves: (i) schools opening and closing, (ii) temperature changesduring the outbreak, and (iii) changes in human behaviour in response to theoutbreak. We fit this model to the reported influenza mortality during the 1918pandemic in 334 UK administrative units and estimate the epidemiologicalparameters. We then use information criteria to evaluate how well these threefactors explain the observed patterns of mortality. Our results indicate thatall three factors are important but that behavioural responses had the largesteffect. The parameter values that produce the best fit are biologicallyreasonable and yield epidemiological dynamics that match the observed datawell.