Table 2 Probability of freedom from poliovirus infection in Australia given continuous negative surveillance findings
|  | Probability of freedom (%)‡ | |||
|---|---|---|---|---|
Design prevalence | 10-5 | 10-6 | ||
Time period | No age effect | Age effect | No age effect | Age effect |
6 months | 61.9 (57.3-68.7) | 70.2 (63.2-78.3) | 50.1 (49.2-51.6) | 51.6 (50.0-52.9) |
1 year | 72.2 (63.8-81.2) | 84.2 (74.1-92.4) | 51.4 (48.0-53.2) | 53.2 (49.7-55.7) |
2 years | 86.2 (74.6-94.3) | 95.6 (87.5-98.9) | 52.8 (45.9-56.3) | 56.2 (49.0-61.2) |
3 years | 92.8 (81.8-98.1) | 98.0 (92.5-99.7) | 54.0 (43.9-59.3) | 59.0 (48.4-66.3) |
4 years | 95.6 (85.9-99.1) | 98.6 (93.9-99.8) | 55.3 (42.1-62.2) | 61.8 (47.8-71.0) |
5 years | 96.9 (88.0-99.5) | 98.7 (94.2-99.9) | 56.5 (40.4-65.0) | 64.3 (47.3-75.1) |
10 years | 97.8 (89.9-99.8) | 98.8 (94.4-99.9) | 61.9 (33.6-76.9) | 74.5 (45.3-89.0) |
20 years | 97.8 (90.0-99.9) | 98.8 (94.4-99.9) | 69.3 (25.1-90.0) | 83.8 (43.1-97.0) |