Table 2.

Characteristics of the high case iterations (ordered by number of cDPV2 cases) for the period of 2022–2026 for

(a) mOPV2
Iteration index	Number of cVDPV2 cases	Number of affected subpopulations	% cases in high R0 blocks*	% cases in low RI coverage blocks+	% cases in blocks representing high transmission areas#
23	44,125	197	80	36	54
55	43,054	182	71	49	40
80	41,443	180	75	42	56
5	39,823	173	81	46	56
93	38,616	159	77	43	51
45	38,191	177	75	40	53
87	37,616	124	58	57	16
81	35,092	131	77	43	52
33	34,485	153	87	44	65
57	34,481	124	62	44	46
(b) best nOPV2
Iteration index	Number of cVDPV2 cases	Number of affected subpopulations	% cases in high R0 blocks*	% cases in low RI coverage blocks+	% cases in blocks representing high transmission areas#
6	26,209	119	75	32	50
9	25,119	101	95	70	43
100	23,682	103	65	61	35
3	23,222	100	87	52	76
66	17,634	73	76	45	50
5	16,860	74	68	84	0
64	14,947	78	53	67	0
98	14,278	90	26	29	3
94	12,944	52	61	91	4
38	12,585	69	44	64	0
(c) worst nOPV2
Iteration index	Number of cVDPV2 cases	Number of affected subpopulations	% cases in high R0 blocks*	% cases in low RI coverage blocks+	% cases in blocks representing high transmission areas#
94	51,270	184	58	46	27
55	50,683	182	67	53	36
6	48,882	179	82	48	52
23	47,918	185	75	39	52
34	46,464	152	60	60	23
66	45,035	160	72	47	48
84	44,178	144	59	54	20
33	43,770	172	76	35	67
100	43,390	132	79	60	43
9	41,759	128	84	55	51

Notes:

^*R₀≥10;

⁺RI coverage ≤0.3,

^#blocks 47–58, 68–69 indicated in Table 1

Abbreviations: cVDPV2, type 2 circulating vaccine-derived polioviruses; type 2 monovalent OPV; nOPV2, type 2 novel OPV; OPV, oral poliovirus vaccine; R₀, basic reproduction number; RI, routine immunization