Implementation of coordinated global serotype 2 oral poliovirus vaccine cessation: risks of inadvertent trivalent oral poliovirus vaccine use

Table 2 Tabulated selected results of Analysis II from Fig. 3 and with the exponential decay scenario

Population with properties like^a	Minimum half-life (years) before exponential decay in inadvertent tOPV use in RI leads to a cVDPV2 outbreak	Minimum duration (years) of rectangular inadvertent tOPV use in RI after the switch that leads to a cVDPV2 outbreak, for indicated inadvertent tOPV RI proportion
Population with properties like^a		0.5 %	1 %	5 %	Proportion (given in parentheses) leading to shortest minimum duration
Hypothetical population
- High R₀	0.16	1.5	1.3	0.85	0.69 (0.25)
- Lower R₀	0.27	2.2	1.9	1.3	1.2 (0.15)
Northern India,
- Under-vaccinated	0.16	1.8	1.2	0.92	0.83 (0.25)
- General	0.17	1.8	1.2	0.96	0.89 (0.2)
Northern Pakistan/Afghanistan
- Under-vaccinated	0.15	1.7	1.1	0.85	0.72 (0.5)
- General	0.22	1.9	1.4	1.0	0.95 (0.15)
Northern Nigeria
- Under-vaccinated	0.22	2.1	1.8	1.0	0.75 (0.4)
- General	0.32	2.7	2.1	1.7	1.6 (0.15)
Ukraine
- Under-vaccinated	0.81	2.7	2.1	1.7	1.6 (0.15)
- General	-^b	-^c	-^c	-^c	-^c

Abbreviations: cVDPV2 serotype 2 circulating vaccine-derived poliovirus, RI routine immunization, tOPV trivalent oral poliovirus vaccine
^aSee Table 1 for assumed properties for each population
^bWe observed either die-out of OPV2-related virus (for half-lives below approximately 4 years) or continued low-level circulation until the end of the analytical time horizon (i.e., 2053) (for longer half-lives)
^cNo cVDPV2 outbreak occurred for durations up to and including the last year of the analytical time horizon, although after > 15 years of inadvertent tOPV use in RI, the cumulative incidence of vaccine-associated paralytic poliomyelitis exceeded the detection threshold

ISSN: 1471-2334