In the 1830–32 epidemic an interesting observation has been made. While Kahlert says that no distinction between age, sex nor rank occurred, Leberscht stated that persons of middle age, especially women in the climacteric period, were attacked with special frequency. This is of interest in view of the findings in the 1918 epidemic. Krimer states for the same epidemic that children under 14 years of age and adults over 45 years were spared by the epidemic.
For the 1836–37 epidemic Finkler records the following: “Most of the patients were adults from 20 to 40 years of age, and of these more women than men were attacked. Curiously, however, the physicians of Würtenberg speak of the great dissemination of the disease among children.”
In 1847–48, among the adult influenza patients, there are said to have been more women than men. According to Canstatt, there were proportionately more children than adults attacked.
In 1889–90, according to Finkler, no age was spared, but persons between 20 and 50 years of age were attacked by preference. No trade was a sure protection. The course of the disease in general was favorable and also quite rapid, unfavorable only in many children during the first few years of life, in many old people, in many debilitated persons, and especially in those suffering from chest affections.
An interesting table of this kind is given us by Leichtenstern. His hospital material included 439 influenza patients, and these he carefully grouped according to age.
| Age. | Influenza admissions, per cent. | General average of admissions, per cent. |
|---|---|---|
| Under 10 years | 0.9 | 0.7 |
| 10–20 years | 14.7 | 8.8 |
| 20–30 years | 40.3 | 27.5 |
| 30–40 years | 19.1 | 23.3 |
| 40–50 years | 10.1 | 15.7 |
| 50–60 years | 7.4 | 12.3 |
| 60–70 years | 5.3 | 8.9 |
| 70–80 years | 1.7 | 2.6 |
| Above 80 years | 0.4 | 0.2 |
Comby found that in Paris only the new-born were noticeably insusceptible to influenza, that children up to 15 years were attacked in the proportion of 40 per cent., and adults in the proportion of 60 per cent. Danchez believed that in families in which all the adults became ill, the little children usually escaped.
Finkler states that in the schools at Bordeaux the older children were first and most frequently attacked. Of the 248 male and female teachers in 41 schools, 153 (61.7 per cent.) developed the disease. Children up to five or six years of age at any rate seem to have been very little affected, while older children were no less susceptible than adults.
Among 47,000 cases of influenza treated by physicians in Bavaria in 1889, the various ages were as follows:
| 1 year | 1.5 per cent. |
| 2–5 | 5.4 per cent. |
| 6–10 | 6.6 per cent. |
| 11–15 | 7.2 per cent. |
| 16–20 | 11.4 per cent. |
| 21–30 | 22.2 per cent. |
| 31–40 | 19.3 per cent. |
| 41–50 | 12.6 per cent. |
| 51–60 | 7.7 per cent. |
| 61–70 | 3.6 per cent. |
| 71–80 | 2.0 per cent. |
| Above 80 | 0.5 per cent. |