Table 2. Probability of infection given exposure, the asymptomatic ratio, and the probability of virus detection estimated by genogroup and genotype based on outbreak data for 2005–2019, Japan.

Groups	(p) Risk of infection (%)	(s) Risk of asymptomatic infection (%)	(q) Risk of virus -positive outcome (%)
GI	62.7 (57.5–67.8)	18.6 (13.6–24.4)	82.7 (76.9–87.5)
GII	62.7 (61.2–64.2)	18.3 (16.8–20.2)	84.4 (82.9–85.9)
GI + GII	63.7 (60.0–67.3)	7.3 (5.0–10.3)	82.2 (78.3–85.6)
GII.4	65.2 (61.7–68.7)	25.8 (22.0–29.9)	85.5 (81.9–88.7)

Note:

Numbers in parentheses represent 95% confidence intervals. All three parameters were assumed to vary with genogroup or genotype. Groups were mutually exclusive (e.g., GI+GII includes outbreaks that involved both GI and GII detected and were not counted as part of the GI group or GII group). Similarly, GII represents outbreaks caused by genogroup GII, excluding those genotyped as GII.4. Note that the GII group could still include GII.4 viruses that were not genotyped.