Smallpox and Season: Reanalysis of Historical Data

Table 1

Monthly weather patterns and smallpox mortality in Northwest frontier province, India, from 1890–1921.

Meteorological element	Univariate model		Multivariate model^¶
	MRR^‡(95% CI^†)	𝑃	MRR^‡(95% CI^†)	𝑃
Rainfall (inch)	0.979 (0.952, 1.003)	.10	0.991 (0.964, 1.018)	.53
Absolute humidity	0.384 (0.309, 0.477)	<.01	0.387 (0.311, 0.481)	<.01

^‡MRR, mortality rate ratio, reflects change in risk of smallpox death per unit (or absolute value) in the meteorological variable in question. ^†CI, confidence interval. ^¶The multivariate model was also adjusted for the calendar year.