Table 4 Probability of freedom from poliovirus infection in Australia given continuous negative surveillance findings based on WHO-recommended notification and stool sampling practices
|  | Probability of freedom (%)‡ | |||
|---|---|---|---|---|
Design prevalence | 10-5 | 10-6 | ||
Time period | No age effect | Age effect | No age effect | Age effect |
6 months | 83.0 (74.3-90.2) | 94.0 (86.7-97.7) | 53.4 (51.6-55.2) | 56.3 (53.8-59.1) |
1 year | 95.4 (88.7-98.5) | 99.2 (96.9-99.8) | 56.7 (52.7-60.2) | 62.3 (57.2-67.4) |
2 years | 99.1 (96.5-99.9) | 99.7 (98.5-100.0) | 62.8 (55.0-69.4) | 72.6 (63.1-80.7) |
3 years | 99.4 (97.2-99.9) | 99.7 (98.6-100.0) | 68.4 (56.9-77.1) | 80.5 (68.2-89.0) |
4 years | 99.4 (97.2-100.0) | 99.7 (98.6-100.0) | 73.2 (58.7-83.1) | 86.0 (72.0-93.8) |
5 years | 99.4 (97.2-100.0) | 99.7 (98.6-100.0) | 77.3 (60.2-87.6) | 89.7 (75.0-96.3) |
10 years | 99.4 (97.2-100.0) | 99.7 (98.6-100.0) | 88.7 (65.3-96.9) | 95.4 (81.1-99.4) |
20 years | 99.4 (97.2-100.0) | 99.7 (98.6-100.0) | 92.7 (68.2-99.3) | 96.0 (82.1-99.7) |