Table 1.

Diagnostic performance of the scent detection dogs stratified by concert

Session	Detection	SARS-CoV-2 infection status		Total no of presented samples	Prevalence	Diagnostic specificity (Sp)	Diagnostic sensitivity (SE)	95% CI Sp	95% CI SE	Diagnostic specificity (regression model)	Diagnostic sensitivity (regression model)	95% CI Sp (regression model)	95% CI SE (regression model)	Rate of concordant results	Positive predictive value (PPV)	Negative predictive value (NPV)
		Positive	Negative
Concert 1	Yes	6	1	475	0.0189	0.9979	0.6667	0.9879 to 0.9999	0.3542 to 0.8794	0.9996	0.7562	0.9988 to 0.9999	0.5144 to 0.9009	0.9916
	No	3	465
Concert 2	Yes	8	1	650	0.0154	0.9984	0.8	0.9912 to 0.9999	0.4902 to 0.9645	0.9992	0.8510	0.9974 to 0.9998	0.6242 to 0.9515	0.9953
	No	2	639
Concert 3	Yes	9	0	689	0.0159	1	0.8182	0.9944 to 1	0.5230 to 0.9677	0.9995	0.78753	0.9991 to 0.9997	0.6716 to 0.8704	0.9971
	No	2	678
Concert 4	Yes	8	0	1026	0.0078	1	1	0.9962 to 1	0.6756 to 1	0.9990	0.87763	0.9913 to 0.9999	0.4412 to 0.9849	1
	No	0	1018
All concerts	Yes	31	2	2840	0.0134	0.9993	0.8158	0.9974 to 0.9999	0.6658 to 0.9078	0.9993	0.8158	0.9974 to 0.9999	0.6658 to 0.9078	0.9968	0.7002	0.9996
	No	7	2800

PPV and NPV were calculated according to Dohoo et al, assuming a prevalence of 0.2%29