Participant characteristics at baseline and events during follow-up
| Baseline characteristics | |
| Sex, n (%) | |
| Male | 570 (24.7) |
| Female | 1742 (75.3) |
| Age, years | |
| Median (IQR) (range) | 60 (49–67) (16–88) |
| Mean (SD) | 58.9 (12.3) |
| Ethnicity, n (%) | |
| Black/African/Caribbean/black British | 11 (0.5) |
| Mixed/multiple ethnic groups | 34 (1.5) |
| South Asian* | 43 (1.9) |
| White | 2191 (94.7) |
| Other | 33 (1.4) |
| Index of multiple deprivation, quartile, n (%)† | |
| 4 (least deprived) | 586 (25.4) |
| 3 | 587 (25.4) |
| 2 | 563 (24.4) |
| 1 (most deprived) | 570 (24.7) |
| Current tobacco smoking, n (%) | |
| Yes | 123 (5.3) |
| No | 2189 (94.7) |
| Educational attainment, n (%)† | |
| Primary/secondary | 229 (9.9) |
| Higher/further (A levels) | 332 (14.4) |
| College/university | 999 (43.2) |
| Postgraduate | 748 (32.4) |
| Self-reported general health, n (%) | |
| Poor | 148 (6.4) |
| Fair | 450 (19.5) |
| Good | 730 (31.6) |
| Very good | 749 (32.4) |
| Excellent | 235 (10.2) |
| Body mass index, kg/m2 | |
| Mean (SD) | 27.4 (6.1) |
| <25 | 952 (41.2) |
| 25–30 | 732 (31.7) |
| >30 | 624 (27.0) |
| Missing | 4 (0.0) |
| ≥1 severe asthma exacerbation‡ in 12 months pre-enrolment, n (%) | |
| Yes | 320 (13.8) |
| No | 1992 (86.2) |
| Asthma treatment, n (%)† | |
| Reliever only§ | 694 (30.0) |
| ICS±reliever¶ | 686 (29.7) |
| LAB±ICS or reliever** | 916 (39.6) |
| Monoclonal antibody†† | 14 (0.6) |
| Events during follow-up | |
| SARS-CoV-2 vaccination (primary course) | |
| ChAdOx1 (Oxford/AstraZeneca) only | 1205 (52.1) |
| BNT162b2 (Pfizer) only | 724 (31.3) |
| Other/mixed regimen | 79 (3.4) |
| Unvaccinated | 304 (13.1) |
| ≥1 severe asthma exacerbation, n (%)‡ | |
| Yes | 411 (17.8) |
| No | 1901 (82.2) |
| ≥1 episode of COVID-19, n (%)‡‡ | |
| Yes | 656 (28.4) |
| No | 1656 (71.6) |
| ≥1 episode of non-COVID-19 ARI, n (%)§§ | |
| Yes | 1115 (48.2) |
| No | 1197 (51.8) |
*Self-defined as Indian, Pakistani, Bangladeshi or Sri Lankan.
†Missing data: index of multiple deprivation (n=6), educational attainment (n=4) and asthma treatment (n=2).
‡Defined as an asthma exacerbation requiring treatment with systemic corticosteroids and/or precipitating emergency department attendance or hospital admission in the 12 months preceding enrolment to COVIDENCE UK.
§Inhaled short-acting beta-agonist or anticholinergic.
¶Regular use of ICS±reliever inhaler, but no LAB or monoclonal antibody treatment.
**Regular use of LAB±ICS or reliever inhaler but no monoclonal antibody treatment.
††Monoclonal antibody treatment, with or without any other treatment.
‡‡Confirmed with positive reverse transcription PRC (RT-PCR) or antigen swab test for SARS-CoV-2.
§§Defined as self-report of doctor-diagnosed or symptom-defined ARI associated with at least one negative RT-PCR or antigen test result for SARS-CoV-2 and no positive RT-PCR or antigen test results for SARS-CoV-2.
ARI, acute respiratory infection; ICS, inhaled corticosteroid; LAB, long-acting bronchodilator inhaler.