Table 2.
Outputs from generalized additive models, with immune marker values associated with 50%, 60%, 70%, 80%, and 90% VE against symptomatic infection
| Assay units | P value immune marker | P value baseline risk score | No. cases | No. noncase | 50% VE (95% CI) | 60% VE (95% CI) | 70% VE (95% CI) | 80% VE (95% CI) | 90% VE (95% CI) |
|---|---|---|---|---|---|---|---|---|---|
| Anti-spike IgG | |||||||||
| AU/ml | 0.003 | <0.001 | 52 | 1155 | 4446 (NC, 12822) | 8413 (NC, 22232) | 17538 (NC, 37929) | 40923 (16748, 125017) | 139306 (57276, NC) |
| BAU/ml | 29 (NC, 83) | 54 (NC, 143) | 113 (NC, 245) | 264 (108, 806) | 899 (369, NC) | ||||
| Anti-RBD IgG | |||||||||
| AU/ml | 0.018 | <0.001 | 52 | 1155 | 2193 (NC, 13614) | 6266 (NC, 29105) | 20700 (NC, 56620) | 63383 (16903, NC) | 295781 (90567, NC) |
| BAU/ml | 17 (NC, 109) | 50 (NC, 232) | 165 (NC, 452) | 506 (135, NC) | 2360 (723, NC) | ||||
| Normalized live-virus neutralization assay | |||||||||
| NF50 | <0.001 | <0.001 | 36 | 412 | 68 (NC, 129) | 91 (NC, 175) | 135 (48, 267) | 247 (101, NC) | 938 (294, NC) |
| Pseudovirus neutralization assay | |||||||||
| ID50 | 0.005 | <0.001 | 47 | 828 | NC | 22 (NC, 76) | 57 (NC, 183) | 185 (NC, NC) | 982 (303, NC) |
| IU/ml | NC | 3 (NC, 11) | 8 (NC, 26) | 26 (NC, NC) | 140 (43, NC) | ||||
ID50: neutralization dilution for 50% virus inhibition; NC: not computed; AU/ml: arbitrary units per mL; BAU/ml: binding antibody units per ml (WHO international standard 20/136), IU/ml: international units per ml (WHO international standard 20/136).
Where CIs were outside the range of values of the assay the limits are reported as NC. VE estimates and CIs are those shown in Fig. 4, at every 10% increment in the y axis. The two-sided P value for each immune marker (column 2) is from the generalized additive models in Fig. 1, showing the strength of the relationship between the antibody value and infection. The P values were not adjusted for multiple comparisons.