Table 2. Transmission Probabilities Included in the Statistical Model With the Corresponding Epidemiologic Measures of Transmissibility.
Type of Transmission | Transmission Group | Time of the Day | Time Perioda | Transmission Probability | Epidemiologic Measure |
---|---|---|---|---|---|
Person-to-Person | Camp participants | Day | Camp period | p1 | R |
Cabin mates | Night | Camp period | p2 | Night cabin SAR | |
Household members | Day and night | Household outbreak period | p3 | Household SAR | |
Cabin mates | Day and night | Camp period | p4b | Cabin-mate SAR | |
Community-to-personc | Camp participants | Day and night | Camp period | b1c | |
Camp participants | Day and night | Postcamp period | b2 | ||
Household members | Day and night | Household outbreak period | b3c |
The camp period was 25–30 April; the postcamp period was 1–7 May; and the household outbreak period extended 10 days from the date of illness onset of the index case.
1 − p4 = (1 − p1)(1 − p2).
b1 and b3 are assumed to be equal to 0 for the primary analysis.
R indicates camp local reproductive number; SAR, secondary attack rate.