Hiroshi Nishiura estimated the numbers of (incident) cases of influenza in Prussian army camps in the region of Arnsberg (Germany) from reported death cases during September 1918 and January 1919. The estimated numbers are presented as dashed line in Figure 1 of [1] ("Onset"). We extracted the estimated numbers of incident cases from Figure 1. For our purpose, the accuracy of the extracted numbers of incident cases is sufficient. In case of need for higher accuracy, we recommend to refer to the original paper [1]. Note that the numbers of incident cases are estimates (as detailed in [1]), the reported original data are the number of fatalities presented as solid line in Figure 1 ("Death") [1]. The numbers of fatalities are kindly given as an electronic supplement of [1] ("Additional File 1"). The variable "Day" is counted from September 9, 1918, onwards. Reference:1. Nishiura H: Time variations in the transmissibility of pandemic influenza in Prussia, Germany, from 1918–19. Theor Biol Med Model 4, 20, 2007. DOI 10.1186/1742-4682-4-20