Table 1 Prior and posterior parameter estimates for the immunological model
From: Estimating long-term vaccine effectiveness against SARS-CoV-2 variants: a model-based approach
Parameter | Symbol | Prior mean (95% confidence interval) | Posterior median (95% credible interval) | Reference for prior mean |
|---|---|---|---|---|
Immunity levels for each vaccine based on prior data on NAT | ||||
Oxford/AstraZeneca AZD1222 vaccine | ||||
IL against Delta for dose 1 relative to convalescent | \({n}_{{AZ},1}\) | 0.07 (0.005, 1.04) | 0.10 (0.08, 0.14) | - |
IL against Delta for dose 2 relative to convalescent | \({n}_{{AZ},2}\) | 0.14 (0.09, 0.22) | 0.36 (0.29, 0.45) | |
IL against Delta for dose 3 relative to convalescent | \({n}_{{AZ},3}\) | 2.0 (0.13, 30.27) | 0.60 (0.45, 0.82) | |
Pfizer-BioNTech BNT162b2 vaccine | ||||
IL against Delta for dose 1 relative to convalescent | \({n}_{{PF},1}\) | 0.30 (0.02, 4.56) | 0.30 (0.24, 0.38) | - |
IL against Delta for dose 2 relative to convalescent | \({n}_{{PF},2}\) | 0.61 (0.39, 0.96) | 0.69 (0.55, 0.87) | |
IL against Delta for dose 3 relative to convalescent | \({n}_{{PF},3}\) | 2.0 (0.13, 30.27) | 0.92 (0.71, 1.19) | |
Moderna mRNA-1273 vaccine | ||||
IL against Delta for dose 1 relative to convalescent | \({n}_{{MD},1}\) | 0.53 (0.04, 7.96) | 0.20 (0.16, 0.27) | - |
IL against Delta for dose 2 relative to convalescent | \({n}_{{MD},2}\) | 1.06 (0.68, 1.67) | 0.93 (0.72, 1.19) | |
IL against Delta for dose 3 relative to convalescent | \({n}_{{MD},3}\) | 2.0 (0.13, 30.27) | 1.13 (0.86, 1.45) | |
Immune escape parameters | ||||
Fold-reduction for Omicron relative to Delta (all vaccines) | VFR | 1.0 (0.001, 2.96) | 5.1 (4.0, 6.8) | |
Immunity level decay parameters | ||||
Half-life of IL decay: short (days) | \({h}_{s}\) | 58 (48, 68) | 35 (31, 38) | |
Half-life of IL decay: long (days) | \({h}_{l}\) | 270 (-122, 662) | 581 (354, 872) | |
Time period for switching (days) | \({t}_{s}\) | 90 (31, 149) | 75 (60, 88) | |
Relationship between IL and protection | ||||
IL relative to convalescent required to provide 50% protection from mild disease | \({{n}_{50}}_{1}\) | 0.2 (0.13, 0.31) | 0.091 (0.066, 0.125) | Prior mean and 95% confidence interval14 |
IL relative to convalescent required to provide 50% protection from hospitalisation | \({{n}_{50}}_{2}\) | 0.03 (0.01, 0.13) | 0.021 (0.012, 0.035) | Prior mean and 95% confidence interval14 |
IL relative to convalescent required to provide 50% protection from death | \({{n}_{50}}_{3}\) | 0.03 (0.01, 0.13) | 0.021 (0.012, 0.036) | Prior based on hospitalisation14 |
Shape parameter | \(k\) | 2.94 (1.76, 4.12) | 3.2 (2.7, 3.7) | Prior mean and 95% confidence interval14 |
