Implementation of coordinated global serotype 2 oral poliovirus vaccine cessation: risks of potential non-synchronous cessation

Table 3 Relationship between the time after the switch until the net reproduction number (R_n) of OPV2 (stage 0) virus exceeds 1, the R_n of OPV2 (stage 0) virus at the time of the switch, and population-specific properties based on the populations from the global model [4] represented in the distributions of Fig. 2 (analysis I without tOPV intensification)

Time (years) since switch until R_n of OPV2 > 1	# subpopulations in time range (out of 520 with OPV-only)	Properties of subpopulations in range
Time (years) since switch until R_n of OPV2 > 1	# subpopulations in time range (out of 520 with OPV-only)	Average R_n before switch^a	R₀ ^b	p^oro	tr	POL3	# tOPV SIA during 2015–2016	TC
1.0–1.45	40	0.41–0.49	12–13	0.3	0.6	0.3	4	0.35
						0.6	4	0.8
						0.6	4	0.95
						0.9	2	0.8
						0.98	2	0.95
1.5–1.74	10	0.37–0.44	11	0.3	0.7	0.3	4	0.5
						0.6	4	0.8
						0.9	2	0.8
						0.98	2	0.95
1.75–1.99	30	0.55	8	0.3	0.7	0.05	4	0.15
		0.35	9	0.3	0.7	0.6	2	0.8
		0.35–0.43	9–12	0.3	0.65–0.7	0.3	4	0.5
						0.6	4	0.5–0.95
						0.9	2	0.8–0.95
2–2.24	103	0.36–0.41	10–11	0.3	0.65–0.7	0.3	4	0.8
						0.6	4	0.8–0.95
						0.9	2	0.8–0.95
						0.98	0	0.8
2.25–2.49	10	0.37	10	0.3	0.7	0.9	2	0.95
2.5–2.74	18	0.33–0.38	9	0.3	0.65–0.7	0.9	2	0.8
2.5–2.74	18	0.33–0.38	9	0.3	0.65–0.7	0.98	0	0.95
2.75–3	31	0.26–0.37	7–9	0.3	0.7–0.72	0.3	4	0.5
						0.6	2	0.8
						0.9	2	0.8
						0.98	0	0.8
				0.8	0.65	0.6	2	0.95
3–3.99	67	0.25–0.39	7–8	0.3	0.7–0.72	0.3	4	0.8
						0.6	2	0.5–0.8
						0.9	2	0.8
						0.98	0	0.95
				0.5	0.72	0.6	2	0.8
				0.8		0.9	2	0.95
				0.8		0.98	0	0.95
		0.38^c	11	0.3	0.65	0.6	4	0.8
		0.53^c	11	0.3	0.65	0.1	4	0.35
4–4.99	2	0.29	7	0.5	0.72–0.73	0.6	2	0.8
4–4.99	2	0.29	7	0.5	0.72–0.73	0.9	2	0.8
5–7.49	30	0.27–0.35	6–8	0.5–0.6	0.73	0.6	2	0.8
5–7.49	30	0.27–0.35	6–8	0.5–0.6	0.73	0.9	2	0.8–0.95
7.5–9.99	3	0.30	7	0.6	0.73	0.6	2	0.8
10–14.99	16	0.31–0.36	7–8	0.6	0.73–0.74	0.6	2	0.8
						0.9	2	0.8–95
						0.98	0	0.95
15–19.99	116	0.3–0.37	7–8	0.6	0.73–0.74	0.9	2	0.8
15–19.99	116	0.3–0.37	7–8	0.6	0.73–0.74	0.98	0	0.95
>20	44	0.3–0.35	6–7	0.6–0.8	0.73–0.75	0.9	2	0.95
>20	44	0.3–0.35	6–7	0.6–0.8	0.73–0.75	0.98	0	0.95

Model input symbols: [3, 16] R ₀ average annual basic reproduction number for WPV of serotype 1, tr take rate of serotype 2 tOPV, POL3 RI coverage with 3 or more non-birth doses, TC true coverage of each SIA, p ^oro proportion of transmissions via oropharyngeal route
^aDefined as the average R_n of OPV2 over the one-year period preceding the switch
^bThe global model uses R₀ for WPV1 to characterize variability in subpopulations, R₀ for serotype 2 WPV equals 0.9 times the values shown in this column
^cPopulation shows long time until R_n of OPV2 exceeds one because of an indigenous cVDPV2 outbreak in one of its subpopulations following the switch and a subsequent mOPV2 response

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