Table 4.

Risk scores used to determine classification of countries according to wild and cVDPV risk and associated sensitivity, specificity and historical probability of an outbreak

Classification	Low	Medium	Medium high	High
Wild-type assessment
Score from risk factors	0–2	3	4–5	6–8
% of observations associated with an outbreak (95% CI)	0.8 (0.4, 1.3)	5.6 (3.1, 8.2)	18.5 (14.3, 23.9)	35.2 (24.2, 46.4)
Sensitivity	100.0%	89.9%	69.7%	24.2%
Specificity	0.0%	67.9%	86.5%	97.5%
cVDPV-type assessment
Score from risk factors	0–3	4–5	6–7	8–9
% of observations associated with an outbreak (95% CI)	0.3 (0.1, 0.6)	2.5 (1.2, 4.1)	12.5 (4.1, 22.2)	34.3 (18.2, 51.6)
Sensitivity	100.0%	88.2%	67.6%	38.2%
Specificity	0.0%	73.1%	93.4%	99.0%