The upper tolerance limits of nonepidemic daily morbidity for influenza and other acute respiratory diseases in the epidemic season.

The start of an influenza epidemic may be detected by comparing actual daily morbidity from influenza and other acute respiratory infections with the upper tolerance limits of this morbidity for nonepidemic years. A method of constructing such tolerance limits for the autumn-winter season, when the probability of an influenza epidemic is greatest, is described. The results are illustrated by data relating to Moscow.