Fig. 1

a-d Histogram of the training dataset for each test and control type overlaid with the corresponding mixture distribution from which the data was generated in the simulation study (training data only). The testing data set are in panels (e) and (f). The first column corresponds to the spike test, and the second to the receptor-binding domain (RBD) test. Training data was sampled from staff at long-term care facilities in Colorado, USA between June and December 2020. Testing data collected from skilled nursing staff in Colorado during May 2020