Skip to main content
. Author manuscript; available in PMC: 2011 Nov 2.
Published in final edited form as: J Infect Dis. 2008 Nov 15;198(10):1427–1434. doi: 10.1086/592454

Table 3.

Protective effect of illness during the first and second pandemic waves against illness during the third wave (winter 1918–1919), based on data from 12 civilian British communities (population 24,706).

Seasonal wave,
illness status		 Illness
in winter		 No illness
in winter		 RR (95% CI) Protective
effect (95% CI)		 P
Summer wave
    Illness 270 2579 1.09 (0.97–1.23) −9%(−22% to 3%) .15
    No illness 1895 19,962
Fall wave
    Illness 262 2813 0.97 (0.86–1.10) 3%(−10% to 14%) .68
    No illness 1895 19,736

NOTE. Data from a British pandemic report [11]. CI, confidence interval; RR, relative risk. Slight differences between data for British civilians in tables 2 and 3 are the result of rounding errors in converting the percentages in the report [11] into numbers.