Table 1. Characteristics of the Matched Case Participants and Controls According to Omicron Infection in the BNT162b2 Analysis.*.
| Characteristic | Omicron BA.1 Infection | Omicron BA.2 Infection | Any Omicron Infection | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Case Participants (N=6264) |
Controls (N=6264) |
SMD | Case Participants (N=20,693) |
Controls (N=20,693) |
SMD | Case Participants (N=25,288) |
Controls (N=25,288) |
SMD | |
| Median age (IQR) — yr | 32 (22–42) | 32 (22–42) | 0.00† | 33 (21–43) | 33 (21–43) | 0.00† | 32 (20–42) | 32 (20–42) | 0.00† |
| Age group — no. (%) | |||||||||
| <20 yr | 1394 (22.3) | 1394 (22.3) | 0.00 | 4,742 (22.9) | 4,742 (22.9) | 0.00 | 6,185 (24.5) | 6,185 (24.5) | 0.00 |
| 20–29 yr | 1207 (19.3) | 1207 (19.3) | 3,873 (18.7) | 3,873 (18.7) | 4,776 (18.9) | 4,776 (18.9) | |||
| 30–39 yr | 1759 (28.1) | 1759 (28.1) | 5,581 (27.0) | 5,581 (27.0) | 6,675 (26.4) | 6,675 (26.4) | |||
| 40–49 yr | 944 (15.1) | 944 (15.1) | 2,982 (14.4) | 2,982 (14.4) | 3,620 (14.3) | 3,620 (14.3) | |||
| 50–59 yr | 610 (9.7) | 610 (9.7) | 2,191 (10.6) | 2,191 (10.6) | 2,493 (9.9) | 2,493 (9.9) | |||
| 60–69 yr | 251 (4.0) | 251 (4.0) | 915 (4.4) | 915 (4.4) | 1,053 (4.2) | 1,053 (4.2) | |||
| ≥70 yr | 99 (1.6) | 99 (1.6) | 409 (2.0) | 409 (2.0) | 486 (1.9) | 486 (1.9) | |||
| Sex — no. (%) | |||||||||
| Male | 3003 (47.9) | 3003 (47.9) | 0.00 | 11,191 (54.1) | 11,191 (54.1) | 0.00 | 13,596 (53.8) | 13,596 (53.8) | 0.00 |
| Female | 3261 (52.1) | 3261 (52.1) | 9,502 (45.9) | 9,502 (45.9) | 11,692 (46.2) | 11,692 (46.2) | |||
| Nationality — no. (%)‡ | |||||||||
| Bangladeshi | 88 (1.4) | 88 (1.4) | 0.00 | 452 (2.2) | 452 (2.2) | 0.00 | 558 (2.2) | 558 (2.2) | 0.00 |
| Egyptian | 378 (6.0) | 378 (6.0) | 1,209 (5.8) | 1,209 (5.8) | 1,443 (5.7) | 1,443 (5.7) | |||
| Filipino | 690 (11.0) | 690 (11.0) | 1,922 (9.3) | 1,922 (9.3) | 2,365 (9.4) | 2,365 (9.4) | |||
| Indian | 677 (10.8) | 677 (10.8) | 2,503 (12.1) | 2,503 (12.1) | 3,093 (12.2) | 3,093 (12.2) | |||
| Nepalese | 57 (0.9) | 57 (0.9) | 282 (1.4) | 282 (1.4) | 312 (1.2) | 312 (1.2) | |||
| Pakistani | 131 (2.1) | 131 (2.1) | 653 (3.2) | 653 (3.2) | 753 (3.0) | 753 (3.0) | |||
| Qatari | 2453 (39.2) | 2453 (39.2) | 8,011 (38.7) | 8,011 (38.7) | 9,572 (37.9) | 9,572 (37.9) | |||
| Sri Lankan | 58 (0.9) | 58 (0.9) | 258 (1.2) | 258 (1.2) | 287 (1.1) | 287 (1.1) | |||
| Sudanese | 310 (4.9) | 310 (4.9) | 910 (4.4) | 910 (4.4) | 1,098 (4.3) | 1,098 (4.3) | |||
| Other§ | 1422 (22.7) | 1422 (22.7) | 4,493 (21.7) | 4,493 (21.7) | 5,807 (23.0) | 5,807 (23.0) | |||
| Calendar week of PCR test — no. (%) | |||||||||
| Dec. 23–29, 2021 | 1145 (18.3) | 1145 (18.3) | 0.00 | 2,494 (12.1) | 2,494 (12.1) | 0.00 | 5,748 (22.7) | 5,748 (22.7) | 0.00 |
| Dec. 30, 2021–Jan. 5, 2022 | 3570 (57.0) | 3570 (57.0) | 11,136 (53.8) | 11,136 (53.8) | 11,677 (46.2) | 11,677 (46.2) | |||
| Jan. 6–12, 2022 | 999 (15.9) | 999 (15.9) | 3,940 (19.0) | 3,940 (19.0) | 4,040 (16.0) | 4,040 (16.0) | |||
| Jan. 13–19, 2022 | 310 (4.9) | 310 (4.9) | 1,752 (8.5) | 1,752 (8.5) | 1,954 (7.7) | 1,954 (7.7) | |||
| Jan. 20–26, 2022 | 94 (1.5) | 94 (1.5) | 698 (3.4) | 698 (3.4) | 886 (3.5) | 886 (3.5) | |||
| Jan. 27–Feb. 2, 2022 | 72 (1.1) | 72 (1.1) | 393 (1.9) | 393 (1.9) | 520 (2.1) | 520 (2.1) | |||
| Feb. 3–9, 2022 | 38 (0.6) | 38 (0.6) | 138 (0.7) | 138 (0.7) | 233 (0.9) | 233 (0.9) | |||
| Feb. 10–16, 2022 | 27 (0.4) | 27 (0.4) | 107 (0.5) | 107 (0.5) | 163 (0.6) | 163 (0.6) | |||
| Feb. 17–20, 2022 | 9 (0.1) | 9 (0.1) | 35 (0.2) | 35 (0.2) | 67 (0.3) | 67 (0.3) | |||
Case participants had test results that were positive for severe acute respiratory syndrome coronavirus 2 by polymerase-chain-reaction (PCR) assay, and controls had test results that were negative by PCR assay. Case participants and controls were matched exactly in a 1:1 ratio according to sex, 10-year age group, nationality, and calendar week of PCR test. Unless otherwise specified, the standardized mean difference (SMD) was defined as the difference between the mean value of a covariate in one group and the corresponding mean value of a covariate in the other group, divided by the pooled standard deviation. An SMD of less than 0.1 indicates adequate matching. Percentages may not total 100 because of rounding. IQR denotes interquartile range.
The SMD is the difference in the mean age between groups, divided by the pooled standard deviation.
Nationalities were chosen to represent the most populous groups in Qatar.
The category of other nationalities includes 57 other nationalities in Qatar among case participants and controls in the analysis of BA.1 infection, 71 other nationalities among case participants and controls in the analysis of BA.2 infection, and 78 other nationalities among case participants and controls in the analysis of any omicron infection.