Table 1.
Characteristics of study participants vaccinated with a monovalent mRNA vaccine as a third dose and a bivalent omicron adapted vaccine as a fourth dose in Denmark. Values are number (percentage) unless stated otherwise
| Characteristics | Vaccine status | ||
|---|---|---|---|
| Three doses (entire cohort) | Fourth dose: bivalent booster | Fourth dose: no bivalent booster* | |
| Total No vaccinated | 2 225 567 | 1 740 417 | 485 150 |
| Mean (SD) age (years) | 66.9 (11.0) | 67.8 (10.7) | 63.7 (11.6) |
| Female | 1 158 395 (52.0) | 922 067 (53.0) | 236 328 (48.7) |
| Ethnicity: | |||
| Nordic countries | 2 081 076 (93.5) | 1 655 558 (95.1) | 425 518 (87.7) |
| Non-western countries | 89 347 (4.0) | 47 037 (2.7) | 42 310 (8.7) |
| Western countries | 55 179 (2.5) | 37 846 (2.2) | 17 333 (3.6) |
| Region of residency: | |||
| Northern Denmark Region | 240 019 (10.8) | 189 601 (10.9) | 50 418 (10.4) |
| Central Denmark Region | 503 569 (22.6) | 398 743 (22.9) | 104 826 (21.6) |
| Region of Southern Denmark | 500 917 (22.5) | 389 586 (22.4) | 111 331 (22.9) |
| Capital Region of Denmark | 622 056 (28.0) | 482 125 (27.7) | 139 931 (28.8) |
| Region Zealand | 359 006 (16.1) | 280 362 (16.1) | 78 644 (16.2) |
| Vaccination priority groups: | |||
| High risk of severe covid-19 | 107 983 (4.9) | 72 707 (4.2) | 35 276 (7.3) |
| Others | 2 117 584 (95.1) | 1 667 710 (95.8) | 449 874 (92.7) |
| Vaccine received as third dose: | |||
| BNT162b2 | 2 029 339 (91.2) | 1 587 589 (91.2) | 441 750 (91.1) |
| mRNA-1273 | 196 228 (8.8) | 152 828 (8.8) | 43 400 (8.9) |
| Vaccine received as fourth dose†: | |||
| Bivalent‡: | 1 740 417 (78.2) | 1 740 417 (100) | NA |
| BNT162b2 with BA.4-5 | 1 157 754 (52.0) | 1 157 754 (66.5) | NA |
| BNT162b2 with BA.1 | 526 397 (23.7) | 526 397 (30.2) | NA |
| mRNA-1273 with BA.1 | 56 266 (2.5) | 56 266 (3.3) | NA |
| Monovalent | 53 025 (2.4) | NA | 53 025 (10.9) |
| None | 432 125 (19.4) | NA | 432 125 (89.1) |
| Comorbidities: | |||
| Asthma | 31 236 (1.4) | 24 998 (1.4) | 6238 (1.3) |
| Chronic respiratory disorder | 52 497 (2.4) | 38 581 (2.2) | 13 916 (2.9) |
| Chronic cardiac disorder | 215 737 (9.7) | 170 772 (9.8) | 44 965 (9.3) |
| Renal disorder | 21 103 (0.9) | 13 664 (0.8) | 7439 (1.5) |
| Diabetes | 80 978 (3.6) | 62 290 (3.6) | 18 688 (3.9) |
| Autoimmune related disorder | 112 385 (5.0) | 84 719 (4.9) | 27 666 (5.7) |
| Epilepsy | 13 933 (0.6) | 10 723 (0.6) | 3210 (0.7) |
| Malignancy | 118 556 (5.3) | 81 375 (4.7) | 37 181 (7.7) |
| Psychiatric disorder | 86 531 (3.9) | 61 330 (3.5) | 25 201 (5.2) |
NA=not applicable; SD=standard deviation.
Percentages within a variable may not sum to 100 owing to rounding.
Not vaccinated with a bivalent booster as a fourth vaccine dose as of 10 December 2022 (end of study period).
BNT162b2 is manufactured by Pfizer-BioNTech and mRNA-1273 is manufactured by Moderna.
Those who received a bivalent vaccine as fourth dose were from the cohort that received three vaccine doses. The reference period consisted of person time of ≥29 days after third and fourth dose vaccination. Figure 1 provides an overview of the study design, and supplementary table S1 provides definitions of variables.