Humoral responses to the BNT162b2 mRNA COVID-19 vaccine in patients with chronic pulmonary disease and controls according to the primary and secondary immunological outcomes at different times during follow-up
| Primary outcome | ||||||
| Time of sampling | Patients (N, %) | Controls (N, %) | Difference (%) | P value | ||
| Responder | Low responder | Responder | Low responder | |||
| Baseline | 0 (0) | 566 (100) | 0 (0) | 581 (100) | 0 | – |
| 3 weeks | 4 (0.88) | 447 (99.1) | 2 (0.43) | 455 (99.6) | 0.45 | 0.67 |
| 2 months | 296 (65.3) | 157 (34.7) | 313 (87.1) | 46 (12.9) | 21.8 | <0.0001 |
| 6 months | 44 (38.9) | 69 (61.1) | 243 (63.9) | 137 (37.1) | 25 | <0.0001 |
| Secondary outcome | ||||||
| Time of sampling | Patients (N, %) | Controls (N, %) | Difference (%) | P value | ||
| Responder | Low responder | Responder | Low responder | |||
| Baseline | 3 (0.01) | 563 (99.9) | 2 (0.6) | 579 (99.4) | 0.59 | 0.98 |
| 3 weeks | 217 (48.1) | 234 (51.9) | 272 (59.5) | 185 (40.5) | 11.4 | 0.0007 |
| 2 months | 414 (91.4) | 39 (8.6) | 354 (98.6) | 5 (1.4) | 7.2 | <0.0001 |
| 6 months | 87 (76.9) | 26 (23.1) | 366 (96.5) | 14 (3.7) | 19.6 | <0.0001 |
Humoral responses are expressed as the proportion of responders and low responders in each group. For the primary outcome, a low responder was defined as an individual having a neutralising antibody index measured in the lower quartile of the study population measured at least 2 weeks after the second dose of the vaccine (2 months sample). In the secondary outcome, a low responder was defined as a combined outcome based on the detection of RBD IgG antibodies <225 AU/mL concomitantly with the detection of neutralising antibodies index <25% measured at least 2 weeks after the second dose of the vaccine (2 months sample). P values for the difference between the proportion of responders in patients versus controls. ‘Baseline samples’ were taken from inclusion and to up to 13 days after the first dose, ‘3 weeks’ samples from 14 days and up to 33 days after the first dose and before administration of a second dose, ‘2 months samples’ were collected between 34 days and up to 90 days after the first dose and only after administration of a second dose; and ‘6 months samples’ from 91 days and up to 273 days after the first dose.