Fig. 1

Contacts between health-care workers. a Contact matrices: the top matrix gives at row X and column Y the aggregate duration of contacts between HCWs of category X and HCWs of category Y; in the second matrix, each (X, Y) entry is normalized by the number of HCWs in category X, giving thus the average time spent by a HCW of category X with all HCWs of category Y; in the bottom matrix, each entry is moreover normalized by the duration (in days) of the data collection. b Number (top) and aggregate duration (bottom) of contacts as a function of the hour of the day, averaged over all the days of data collection. Data are shown for all contacts and for some specific categories. MED medical doctors; NUR nurses; NURA nurses’ aids; HKS housekeeping staff