Table 2. Sample characteristics.
Antibody level values and characteristics for TwinsUK and Avon Longitudinal Study of Parents and Children (ALSPAC) individuals sampled in Q2 and Q4 antibody collections. Individuals are stratified by vaccination status at time of sampling. Data shown for individuals sampled at least 4 weeks after first vaccination, and at least 2 weeks after second or third vaccination to allow time for antibody generation. The anti-Spike antibody level assay range is 0.4–250 BAU/mL for Q2 results and 0.4–25,000 BAU/mL for Q4 results, with a positive threshold of 0.8 BAU/mL. Categories with fewer than five individuals are suppressed.
| Cohort | TwinsUK | ALSPAC | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Testing period | Q2 | Q4 | Q2 | Q4 | Q2 | ||||||
| Vaccination status | All results | All results | Not vaccinated | Single-vaccinated | Double-vaccinated | Double-vaccinated | Triple-vaccinated | All results | Not vaccinated | Single-vaccinated | Double-vaccinated |
| n | 4256 | 3575 | 330 | 1375 | 748 | 691 | 1937 | 1779 | 36 | 1459 | 284 |
| Age (years): Median (IQR) | 63.0 (49.0, 72.0) | 63.0 (51.0, 72.0) | 38.0 (31.0, 44.0) | 63.0 (56.0, 69.0) | 70.0 (56.0, 77.0) | 49.0 (38.0, 59.0) | 69.0 (60.0, 74.0) | 60.0 (57.0, 62.0) | 57.5 (52.75, 62.25) | 60.0 (57.0, 63.0) | 59.0 (56.0, 61.0) |
| Sex: Male, n (%) | 518/4255 (12.2%) | 447/3574 (12.5%) | 48/330 (14.5%) | 178/1375 (12.9%) | 88/748 (11.8%) | 103/691 (14.9%) | 225/1937 (11.6%) | 451/1779 (25.4%) | 8/36 (22.2%) | 397/1459 (27.2%) | 46/284 (16.2%) |
| Ethnicity: Other than White, n (%) | 118/4219 (2.8%) | 96/3536 (2.7%) | 16/329 (4.9%) | 29/1368 (2.1%) | 19/739 (2.6%) | 26/686 (3.8%) | 39/1914 (2.0%) | 26/1779 (1.5%) | <5 | 20/1459 (1.4%) | 5/284 (1.8%) |
| BMI: Median (IQR) | 24.75 (22.15, 27.99) | 24.76 (22.2, 27.98) | 22.72 (20.94, 25.42) | 24.86 (22.27, 28.28) | 24.99 (22.23, 28.07) | 23.91 (21.62, 27.58) | 24.87 (22.3, 27.87) | 25.7 (23.23, 28.7) | 25.63 (23.13, 28.04) | 25.71 (23.25, 28.77) | 25.65 (23.02, 28.6) |
| Advised on ‘Shielded Patient List’: Yes, n (%) | 341/4109 (8.3%) | 279/3530 (7.9%) | 8/329 (2.4%) | 82/1374 (6.0%) | 86/748 (11.5%) | 23/691 (3.3%) | 190/1936 (9.8%) | 67/1754 (3.8%) | <5 | 45/1443 (3.1%) | 22/276 (8.0%) |
| Self-rated health: Poor, Fair, n (%) | 357/4082 (8.7%) | 290/3407 (8.5%) | 15/316 (4.7%) | 134/1364 (9.8%) | 60/737 (8.1%) | 42/656 (6.4%) | 168/1871 (9.0%) | 167/1778 (9.4%) | <5 | 137/1459 (9.4%) | 28/283 (9.9%) |
| Zygosity: Monozygotic, n (%) | 2722/4253 (64.0%) | 2280/3573 (63.8%) | 248/328 (75.6%) | 883/1375 (64.2%) | 459/748 (61.4%) | 490/689 (71.1%) | 1170/1937 (60.4%) | – | – | – | – |
| Anti-Spike antibody level value (BAU/mL): Median (IQR) | 80.78 (18.55, 250.0) | 10403.0 (3510.0, 20224.0) | 0.4 (0.4, 0.4) | 53.3 (22.72, 121.2) | 250.0 (250.0, 250.0) | 1317.0 (337.0, 5202.5) | 13694.0 (8153.0, 23543.0) | 58.93 (21.25, 247.5) | 10.53 (0.4, 48.69) | 43.42 (17.98, 106.65) | 250.0 (250.0, 250.0) |
| Anti-Spike antibody status: Positive, n (%) | 3372/3912 (86.2%) | 3423/3445 (99.4%) | 79/330 (23.9%) | 1357/1375 (98.7%) | 745/748 (99.6%) | 690/691 (99.9%) | 1936/1937 (99.9%) | 1745/1779 (98.1%) | 23/36 (63.9%) | 1440/1459 (98.7%) | 282/284 (99.3%) |
| Anti-Nucleocapsid antibody status, Q2: Positive, n (%) | 460/3893 (11.8%) | 333/2887 (11.5%) | 60/329 (18.2%) | 156/1368 (11.4%) | 87/743 (11.7%) | 85/565 (15.0%) | 160/1624 (9.9%) | 167/1757 (9.5%) | <5 | 133/1438 (9.2%) | 31/283 (11.0%) |
| Anti-Nucleocapsid antibody status, Q4: Positive, n (%) | 524/2998 (17.5%) | 618/3447 (17.9%) | 80/290 (27.6%) | 197/1130 (17.4%) | 95/602 (15.8%) | 179/691 (25.9%) | 263/1937 (13.6%) | – | – | – | – |
| Weeks since first vaccination: Median (IQR) | 10.0 (6.0, 12.0) | 42.0 (38.0, 45.0) | –5.0 (-8.0,–3.0) | 8.0 (6.0, 9.0) | – | – | – | – | – | 6.0 (5.0, 8.0) | – |
| First vaccination received: AZD1222 (Oxford/AZ), n (%) | 2124/3591 (59.1%) | 1980/3378 (58.6%) | 70/275 (25.5%) | 1103/1374 (80.3%) | – | – | – | – | – | 1235/1459 (84.6%) | – |
| First vaccination received: BNT162b2 (Pfizer BioNTech), n (%) | 1410/3591 (39.3%) | 1336/3378 (39.6%) | 170/275 (61.8%) | 266/1374 (19.4%) | – | – | – | – | – | 224/1459 (15.4%) | – |
| Weeks since second vaccination: Median (IQR) | –1.0 (-4.0, 2.0) | 32.0 (28.0, 34.0) | – | – | 3.0 (2.0, 5.0) | 25.0 (20.0, 28.0) | 33.0 (31.0, 35.0) | – | – | – | 4.0 (2.0, 6.0) |
| Second vaccination received: AZD1222 (Oxford/AZ), n (%) | 1858/3266 (56.9%) | 1888/3275 (57.6%) | – | – | 212/748 (28.3%) | 411/691 (59.5%) | 1065/1934 (55.1%) | – | – | – | 50/284 (17.6%) |
| Second vaccination received: BNT162b2 (Pfizer BioNTech), n (%) | 1357/3266 (41.5%) | 1330/3275 (40.6%) | – | – | 532/748 (71.1%) | 241/691 (34.9%) | 858/1934 (44.4%) | – | – | – | 234/284 (82.4%) |
| Weeks since third vaccination: Median (IQR) | –28.0 (-30.0,–26.0) | 5.0 (3.0, 7.0) | – | – | – | – | 5.0 (4.0, 8.0) | – | – | – | – |
| Third vaccination received: mRNA-1273 (Moderna), n (%) | 293/2149 (13.6%) | 337/2400 (14.0%) | – | – | – | – | 203/1903 (10.7%) | – | – | – | – |
| Third vaccination received: BNT162b2 (Pfizer BioNTech), n (%) | 1828/2149 (85.1%) | 2026/2400 (84.4%) | – | – | – | – | 1677/1903 (88.1%) | – | – | – | – |
| SARS-CoV-2 infection status (serology-based) at time of antibody testing: Evidence of natural infection, n (%) | 891/4190 (21.3%) | 977/3561 (27.4%) | 98/330 (29.7%) | 304/1375 (22.1%) | 157/748 (21.0%) | 245/691 (35.5%) | 464/1937 (24.0%) | 187/1757 (10.6%) | 23/36 (63.9%) | 133/1438 (9.2%) | 31/283 (11.0%) |
| SARS-CoV-2 infection status (self-reported), Q2: Suspected case, n (%) | 477/4092 (11.7%) | 399/3428 (11.6%) | 35/320 (10.9%) | 183/1365 (13.4%) | 67/739 (9.1%) | 81/662 (12.2%) | 197/1882 (10.5%) | 302/1675 (18.0%) | 5/33 (15.2%) | 240/1374 (17.5%) | 57/268 (21.3%) |
| SARS-CoV-2 infection status (self-reported), Q2: Confirmed case, n (%) | 597/4092 (14.6%) | 492/3428 (14.4%) | 57/320 (17.8%) | 218/1365 (16.0%) | 112/739 (15.2%) | 107/662 (16.2%) | 256/1882 (13.6%) | 40/1675 (2.4%) | <5 | 29/1374 (2.1%) | 11/268 (4.1%) |
| SARS-CoV-2 infection status (self-reported), Q4: Suspected case, n (%) | 478/4134 (11.6%) | 404/3543 (11.4%) | 34/330 (10.3%) | 183/1375 (13.3%) | 70/748 (9.4%) | 78/691 (11.3%) | 204/1936 (10.5%) | – | – | – | – |
| SARS-CoV-2 infection status (self-reported), Q4: Confirmed case, n (%) | 817/4134 (19.8%) | 751/3543 (21.2%) | 92/330 (27.9%) | 306/1375 (22.3%) | 145/748 (19.4%) | 202/691 (29.2%) | 357/1936 (18.4%) | – | – | – | – |