[Study and improvement of Reed-Frost model].

The purpose of this paper is to modify the Reed-Frost theory of epidemics with the underlying assumptions of the model including the occurrence of inapparent infections, and their influence on the course of the epidemic. With this model two epidemics were computed: (1) the Aycock outbreak of measles in a New England boy-boarding school in 1934; (2) the outbreak of chickenpox in a Shanghai kindergarten in 1950. The calculated and observed results were well in agreement. A substantial improvement in fitness was shown as measured by chi-square tests. As presented, the model offers a reasonably good explanation on the occurrence of inapparent infections and its effect on the pattern of the disease.