Table 1.
Baseline characteristics for 1,076 ChAdOx1 nCoV-19 participants in the phase 1/2 (COV001) and phase 2/3 (COV002) trials who received ChAdOx1 nCoV-19 vaccine with genotype data available and for the 1,069 individuals who either experienced a breakthrough infection after 21 days or who did not experience a breakthrough up to time of censoring
| Characteristic (range where applicable) | Genotyped cohort (ChAdOx1 vaccinated) n = 1,076 | No reported breakthrough infection (n = 957) | Breakthrough infection reported (n = 112) | Evidence of difference between breakthrough groups (P) |
|---|---|---|---|---|
| Age at recruitment | 37.0 (30.0–47.0) | 37.0 (30.0–47.0) | 37.0 (28.8–48.0) | NS |
| 18–55 years, number (%) | 1076 (100) | 957 (100) | 112 (100) | |
| Missing, number (%) | 0 (0) | 0 (0) | 0 (0) | NS |
| Sex, number (%) | ||||
| Female | 572 (53.2) | 514 (53.7) | 56 (50.0) | |
| Male | 504 (46.8) | 443 (46.3) | 56 (50.0) | NS |
| BMI | ||||
| Median (IQR) | 24.7 (22.6–27.5) | 24.7 (22.5–27.5) | 25.2 (22.7–28.3) | NS |
| Ethnic group, number (%) | ||||
| White | 974 (90.5) | 865 (90.4) | 102 (91.1) | |
| Asian | 50 (4.7) | 44 (4.6) | 6 (5.3) | |
| Black | 10 (0.9) | 9 (0.9) | 1 (0.9) | |
| Mixed | 29 (2.7) | 26 (2.7) | 3 (2.7) | |
| Other | 13 (1.2) | 13 (1.4) | 0 (0) | |
| Not reported/missing | 0 (0) | 0 (0) | 0 (0) | NS |
| Health and social care setting workers (HCWs), number (%) | ||||
| Not HCW | 590 (54.8) | 539 (56.3) | 48 (42.9) | |
| HCW unknown COVID contacts | 101 (9.4) | 91 (9.5) | 10 (8.9) | |
| HCW with ≤1 COVID contacts | 267 (24.8) | 226 (23.6) | 40 (35.7) | |
| HCW with >1 COVID contacts | 118 (11.0) | 101 (10.6) | 14 (12.5) | 0.02 |
| Comorbidities, number (%) | ||||
| Cardiovascular | 35 (3.3) | 29 (3.0) | 6 (5.2) | NS |
| Respiratory | 73 (6.8) | 59 (6.1) | 14 (12.5) | 0.02 |
| Diabetes | 9 (0.8) | 7 (0.7) | 2 (1.8) | NS |
| Interval between first and second vaccine, number (%) | ||||
| <6 weeks | 12 (1.1) | 11 (1.1) | 1 (0.9) | |
| 6–8 weeks | 151 (14.0) | 133 (13.9) | 17 (15.2) | |
| 9–11 weeks | 257 (23.9) | 220 (23.0) | 33 (29.5) | |
| ≥12 weeks | 556 (51.7) | 501 (52.4) | 53 (47.3) | |
| None | 100 (9.3) | 92 (9.6) | 8 (7.1) | NS |
| Vaccines received before infection occurring, number (%) | ||||
| SD | 499 (46.4) | 463 (48.4) | 35 (31.3) | |
| SD/SD | 400 (37.2) | 342 (35.7) | 54 (48.2) | |
| LD/SD | 167 (15.5) | 143 (15.0) | 22 (19.6) | |
| SD/LD | 10 (0.9) | 9 (0.9) | 1 (0.9) | 0.005 |
| HLA carrier, number (%) | ||||
| HLA-DQB1*06 | 474 (44.1) | 436 (45.6) | 38 (33.9) | 0.02 |
| DRB1-71E/R | 881 (81.9) | 784 (81.9) | 92 (82.1) | NS |
| HLA status, number (%) | ||||
| Carrying DRB1-71E/R with no DQB1*06 | 532 (49.4) | 464 (48.5) | 63 (56.3) | |
| Remainder | 419 (38.9) | 377 (39.4) | 40 (35.7) | |
| Carrying DQB1*06 with no DRB1-71E/R | 125 (11.6) | 116 (12.1) | 9 (8.0) | NS |
Seven individuals were not included in the breakthrough analysis as they experienced breakthrough infection within 22 days of receiving their first vaccine. Statistical differences were tested across groups using chi-squared tests or Fisher exact tests if any group contained fewer than five observations. NS, not significant.