Table 1.
Baseline characteristics of participants at time of entry into study.
| Delta N = 92 1821 | Omicron N = 92 1821 | p-value2 | |
|---|---|---|---|
| Week of entry | >0·99 | ||
| 2021–49 | 1 714 (1·9%) | 1 714 (1·9%) | |
| 2021–50 | 8 486 (9·2%) | 8 486 (9·2%) | |
| 2021–51 | 33 924 (36·8%) | 33 924 (36·8%) | |
| 2021–52 | 28 452 (30·9%) | 28 452 (30·9%) | |
| 2022–01 | 14 501 (15·7%) | 14 501 (15·7%) | |
| 2022–02 | 3 505 (3·8%) | 3 505 (3·8%) | |
| 2022–03 | 1 600 (1·7%) | 1 600 (1·7%) | |
| Age (years) | >0·99 | ||
| [18,40) | 50 073 (54·3%) | 50 073 (54·3%) | |
| [40,65) | 35 353 (38·4%) | 35 353 (38·4%) | |
| [65,80) | 5 219 (5·7%) | 5 219 (5·7%) | |
| [80,Inf) | 1 537 (1·7%) | 1 537 (1·7%) | |
| Sex | 0·21 | ||
| Female | 50 265 (54·5%) | 49 996 (54·2%) | |
| Male | 41 917 (45·5%) | 42 186 (45·8%) | |
| Vaccination3 | <0·001 | ||
| Unvaccinated | 30 234 (32·8%) | 10 436 (11·3%) | |
| Primary vaccination | 55 549 (60·3%) | 64 918 (70·4%) | |
| Booster | 6 399 (6·9%) | 16 828 (18·3%) | |
| Comorbidity | <0·001 | ||
| None | 77 771 (84·4%) | 79 351 (86·1%) | |
| Medium-risk | 11 556 (12·5%) | 10 422 (11·3%) | |
| Very-high-risk | 2 855 (3·1%) | 2 409 (2·6%) | |
| Region | <0·001 | ||
| Grand Est | 11 809 (12·8%) | 8 618 (9·3%) | |
| Auvergne-Rhône-Alpes | 17 064 (18·5%) | 16 686 (18·1%) | |
| Île-de-France | 6 179 (6·7%) | 20 465 (22·2%) | |
| Pays de la Loire | 3 107 (3·4%) | 5 074 (5·5%) | |
| Bretagne | 2 618 (2·8%) | 3 814 (4·1%) | |
| Nouvelle-Aquitaine | 6 792 (7·4%) | 6 895 (7·5%) | |
| Hauts-de-France | 6 425 (7·0%) | 8 397 (9·1%) | |
| Normandie | 2 223 (2·4%) | 3 664 (4·0%) | |
| Bourgogne-Franche-Comté | 5 834 (6·3%) | 3 611 (3·9%) | |
| Corse | 44 (0·5%) | 614 (0·7%) | |
| Occitanie | 13 400 (14·5%) | 6 930 (7·5%) | |
| Overseas France | 1 619 (1·8%) | 525 (0·6%) | |
| Provence-Alpes-Côte d'Azur | 13 242 (14·4%) | 5 313 (5·8%) | |
| Centre-Val de Loire | 1 376 (1·5%) | 1 576 (1·7%) |
1n (%) .
2Pearson's Chi-squared test
37.6% of individuals classified as unvaccinated had an incomplete primary vaccination, of whom 35% had received the first dose less than 14 days before the virological diagnosis. 82% of individuals with and incomplete primary vaccination received one dose. The primary vaccination series consisted of 1 dose for 6% of individuals, 2 doses for 87% and 3 doses for 7%. Individuals receiving a booster vaccination received a total of 3 doses for 92% of cases and 2 doses for 8% of cases. Baseline characteristics of population before matching (n = 774 696) are available in the appendix.