“The following is believed to have been the commencement of the outbreak, and for these facts I am indebted to Dr. Francis Walker, Medical Officer of Health, Spilsby, R. S. D. Mrs. N., residing at East Keal Hall, went to London (Forest Hill) on a visit on November 11th. She visited Barnum’s Show on November 13th. She became ill on the night of the 14th. Her symptoms were those of a cold, attended with sore throat. No one else so far as she knew was ill in this way in the house before her. She left Forest Hill on November 16th, still feeling very unwell, and went to stay with friends at Kensington. She was too ill to return home till November 23d, at which time she was still feeling very weak. She heard from Forest Hill that, directly after she left one of the inmates of the house where she had been visiting fell ill with symptoms similar to her own. Within a few days, probably about the 27th of November (the exact date is not fixed), of her return home, her son, aged four, became unwell with what appeared to be an ordinary cold, but the child had epistaxis; he soon recovered, but during the next fortnight the four servants in the house were ill with what were said to be ‘colds,’ one of them also had epistaxis. On January 2d another son, aged six, was ill with ‘cold’ for a few days; he went out and had a relapse, which compelled him to stay in the house for another week.
“On January 3d, Mrs. N. again fell ill with ‘a bad cold,’ attended with headache, backache and epistaxis. She was in bed two days and felt miserable and prostrate for more than a week after. On January 5th, Mr. N., her husband, had headache, backache, and general soreness ‘all over.’ On January 10th, the boy, aged four, who was first attacked after his mother’s return from London, again became ill, his symptoms being the same as before. The only other remaining member of the family who had managed to escape an attack of ‘cold’ up to this date, was said to have felt ill the day the boy had his second attack; but the illness of this individual was slight, and only caused suffering for one night. Thus between the return of the mother on November 23d and January 10th all the inmates of this house, nine in number, had an attack of illness, evidently of the same nature. A boy who works in Mr. N.’s yard was taken ill with influenza about the end of November. He lives in the village. After his illness his four brothers also were ill. Dr. Walker says that ‘about the end of November’ cases of like illness were beginning to crop up in East Keal. Mrs. W., the wife of the village grocer and baker, who waited on customers in the shop and never left the shop or house, was taken ill on the afternoon of November 30th. Next morning, December 1st, her husband and six children were all attacked in the same way with what is now recognized to have been marked influenza. The only inmate of the house who escaped was a youth employed to deliver bread and groceries in a cart in the neighboring village.”
Leichtenstern relates that a physician traveling from Berlin on the 10th of December became sick in his home town, Elgesburg, on the 8th of December, but he made several visits and a few days later those people seen by him fell sick, while otherwise there were no cases of influenza in the town or its neighborhood. These cases would probably have fallen in Group C., of Murphy’s classification.
Intimacy of family contact.—We have been able to discover in a representative number of families in which influenza has occurred, not only what individuals slept in the various rooms of the household, but also what individuals slept in the same bed with influenza cases. We can, therefore, study for the 1920 epidemic three degrees of contact; contact by sleeping with a case of influenza; by sleeping in the same room but a different bed; and general contact by being in the family, but sleeping in another room. For brevity we designate these, “sleeping,” “room” and “family” contact. We have established similar information for 1918, after eliminating families in which deaths or births or other additions or losses had occurred during or subsequent to the 1918 pandemic, in which there has been a change of address, in which the cases are so widely separated that we have designated them unrelated, and finally, those families in which the information has been insufficient. With the remaining we have assumed that the distribution within the household has been the same in both epidemics. Statistics are available on 1,734 individuals who in 1918 were exposed to a prior case in the family. Of these, 462 developed influenza and 1,272 did not. 26.6 per cent. of exposed individuals in families contracted influenza, without respect to the degree of exposure.
| Intimacy of contact. | Number so exposed. | Number infected. | Per cent. infected. |
|---|---|---|---|
| “Sleeping” | 360 | 166 | 45.2 |
| “Room” | 303 | 59 | 19.5 |
| “Family” | 1,064 | 273 | 22.3 |
45.2 per cent. of individuals sleeping with cases of influenza in 1918 contracted the disease; 19.5 per cent. of those sleeping in the same room, but different beds did so; 22.3 per cent. of those living in the same family, but sleeping in other rooms contracted the disease.
Sleeping contact is more productive of influenza than are the less intimate forms.
Throughout this study the fact that there are multiple possible sources of infection both outside and often within the family complicates the picture.
The results for 1920 are similar. Here, 30.0 per cent. of all individuals sleeping with cases of influenza contracted the disease, 17.7 per cent. of room exposures contracted it, while but 11.5 per cent. of family exposures were attacked.
Four hundred and sixty-three or 29.1 per cent. of the total of 2,193 individuals exposed in 1920 had had the disease in the 1918 pandemic. Did they show by reason of any immunity a lower attack rate for the same degree of exposure than other individuals in 1920?