Long-Range Observation on Banal Infections of the Respiratory Tract in Inhabitants of a Certain Area

Abstract

This is to report the epidemiological investigation of banal infections of the respiratory tract, especially of common cold. That is, the tracing investigation of these diseases was made on 497 persons of 115 families in a certain area of Tokyo by inquiries per family once a week for one year from Feb. 19, 1956.
Results were as follows.
1) The average frequency of affections in each person was 5 times a year, but there was some difference depending on sex and age, and also individual difference was great. The existence of those who were frequently affected by these diseases was proved logically. It was also clarified that the distribution of incidence in people of 25 54 years old suggested a certain rule..
2) The infection was more often carried into a family by the younger than the older. The secondary attack rate was comparatively low though there was some difference depending on age regardless of the age of index case. This fact proved that some of these discases were fairly non-infectious.
3) It was also proved that coldness was an important factor to accelerate the propagation of these diseases. Clinical symptoms and therapeutic states were clarified.