Table 3.

Summary of parameters for 51 post-World War II Western European and North American smallpox outbreaks.

	Number of Outbreaks Identified	Median for Initial R	Median for Number of Generations	Median for Number of Total Cases	Median for Number of Deaths
Overall	51	2	1	4	1
Reporting Status
Incompletely reported	21	0	0	1	0
Reported in detail	30	2	2	13	2
Outbreak Setting
Community	11	1	1	2	1
Mixed	8	2	3	22	3
Hospital	11	12	2	20	4
Clinical Presentation of Index Case
Hemorrhagic	6	5	2	16.5	4
Atypical*	13	4	3	27	4
Typical	9	1	1	2	1
Index Case Identified as Smallpox
No	14	5	3	27.5	6
Yes	16	1	1	3	1

* Atypical: index cases with a milder illness (usually seen with a previous vaccination for smallpox) or a rash not characteristic of smallpox.