Table 3 Explanatory variables used in the risk score to assess vaccine-derived poliomyelitis outbreak risk, based on a regression analysis of data from 2003 to 2016
Variable | Factor | p-value | Risk estimate | Risk score |
|---|---|---|---|---|
Population Immunity | ||||
Routine | 95+ | baseline | 0 | |
immunisation | 85–95 | <0.001 | 1.51 (1.23, 1.85) | 1 |
75–85 | 2.27 (1.85, 2.78) | 1 | ||
65–75 | 3.42 (2.79, 4.19) | 2 | ||
<65 | 5.15 (4.2, 6.31) | 2 | ||
Under-immunised | 0–20% of non-polio AFP reporting 0–2 OPV doses | baseline | 0 | |
>20% of non-polio AFP reporting 0–2 OPV doses | 0.18 | 1.48 (0.84, 2.61) | 1 | |
Zero dose | 0–20% of non-polio AFP reporting 0 OPV doses | baseline | 0 | |
>20% of non-polio AFP reporting 0 OPV doses | 0.427 | 0.40 (0.04, 3.82) | 1 | |
Susceptibility | ||||
cVDPV outbreaks in last 0–4 years | No | baseline | 0 | |
Yes | 0.005 | 3.41 (1.44, 8.07) | 1 | |
Population displacement | 0–10% of population displaced | baseline | 0 | |
>10% of population displaced | 0.005 | 3.25 (1.43, 7.38) | 1 | |
Livebirths per year | <500,000 | baseline | 0 | |
<1,000,000 | 0.004 | 6.94 (1.86, 25.93) | 2 | |
+1 mill | <0.001 | 29.32 (8.3, 103.48) | 4 | |