TABLE 1.

Place of contact for each retrospective passive outbreak investigated

Place or form of contact	No. of outbreaks	% of total no. of outbreaks
School	5	7.7
Hospital	13	20.0
Nursing home	3	4.6
Public house	4	6.2
Work	5	7.7
Shared house or flat	4	6.2
Nursery	1	1.5
Farm	1	1.5
Family and/or friends	9	13.8
Community and/or prisona	12	18.5
Other	8	12.3
Total	65	100

^aFive of 20 cases in one community outbreak had occurred in prison. Similarly, in another incident of isoniazid-resistant TB in London, England, several cases were associated with a prison. The prison outbreaks have been counted as part of community outbreaks rather than as a specific prison incident.