A Second Approximation to Soper's Epidemic Curve

Abstract

H. E. Soper developed a theory of the epidemic curve for a disease like measles. To a low order of approximation he found that the relation between the time T (measured in incubation periods as a unit from a zero value at the peak of the epidemic) and the ratio C/Co of the case rate C at time T to the case rate Co when maximum (the cases being expressed as fractions of . the number of susceptibles present when the epidemic is near its peak) is [image] The authors find that to a much higher degree of exactness the relationship is [image].