Mild.—A case is recorded as mild if the individual has remained in bed three days or less; Average, if in bed four to seven days; Severe, if in bed over seven days. Pneumonia. This designation is added to that of “severe” only in case the physician made such a diagnosis, or if the evidence under “symptomatology” leaves no doubt as to the condition.
Examples of individual exceptions to the preceding general classification are as follows: An individual in bed two days, but sick for three weeks might be recorded as average. A mother, with a family of sick children and who spent no time in bed may have been a severe case of influenza. In fact, we have allowed ourselves a certain latitude in individual cases in classifying both the diagnosis and the severity of the disease.
In the final tabulation we have included both the “Yes” and the “Probable” as being cases of influenza. This has been done after a careful comparison of both groups.
As a check upon the reliability of the work we have compared our results for the 1918 epidemic with those reported by Frost and Sydenstricker and have discovered that with regard to the general subject discussed in both studies there is close agreement. This is important in view of the long period that has elapsed between the first pandemic and the time of our survey, and because we are unable to compare our tables of incidence for 1918 with those for the city or the state at large. Our own records do not place the date of occurrence of the disease in 1918 any more closely than by month.
We have compared our 1920 incidence curves with those of Massachusetts and find a close correspondence, particularly in the date of onset, peak, and disappearance of the epidemic. We have done likewise for the occurrence of the disease in the city of Boston at large (Chart XIV).
In the past but few house-to-house canvasses have been made with relation to influenza. Auerbach, following the 1889 epidemic, collected statistics on 200 families distributed throughout the city of Cologne. Abbott, while not conducting a canvass, did obtain a certain amount of valuable information by letters addressed to physicians, institutions and corporations throughout the State of Massachusetts.
There is fairly abundant literature on the disease as it occurred in institutions. Moody and Capps, in a study of the epidemic in Chicago in December, 1915 and January, 1916, made a survey of the personnel and inmates of four institutions in that city. Among other rather numerous statistical compilations from institutions we may mention that of Hamilton and Leonard which was devoted particularly to a study of immunity, and that of Stanley at San Quentin Prison, California.
Garvie has reported his personal experience with influenza in an industrial area and discusses the disease as it has occurred in families in his private practice.
Carnwath reports a “block census” undertaken by Dr. Niven in Manchester, England. This is of the same nature as our own work. Reeks has made a detailed house survey of 2,757 persons in New Britain, Connecticut. D. W. Baker has conducted somewhat similar surveys for the New York Department of Health, and Winslow and Rogers quote the excellent record of the Visiting Nurse Association of New Haven, in which they have information for all of the families cared for by the nurses. This, however, is a collected group and does not correspond with the so-called block census.
CHART XIV.