Table 1.
Antibody responses to the receptor‐binding domain of the ancestral SARS‐CoV‐2 virus (WT) and to B.1.1.7, B.1.351, and B.1.617.2 using the haemagglutination test (HAT)
| Age groups | WT | B.1.1.7 (alpha) | B.1.351 (beta) | B.1.617.2 (delta) |
|---|---|---|---|---|
| 20–39 (n = 41) | ||||
| Numbr positive (%) | 7 (16.7) | 5 (11.9) | 5 (11.9) | 6 (14.3) |
| HAT titre mean (±SD) | 50.7 (146.2) | 25.9 (101.2) | 42.0 (200.2) | 22.9 (73.2) |
| HAT titre (IQR) | 0 (20) | 0 (0) | 0 (20) | 0 (0) |
| 40–59 (n = 48) | ||||
| Number positive (%) | 12 (25.5) | 5 (10.6) | 5 (10.6) | 5 (10.6) |
| HAT titre mean (±SD) | 38.8 (104.9) | 22.5 (67.4) | 12.5 (25.3) | 8.9 (27.0) |
| HAT titre median (IQR) | 0 (25) | 0 (20) | 0 (20) | 0 (0) |
| ≥60 (n = 21) | ||||
| Number positive (%) | 3 (14.3) | 2 (9.5) | 2 (9.5) | 2 (9.5) |
| HAT titre mean (±SD) | 23.8 (70.6) | 18.1 (69.8) | 13.3 (38.1) | 24.8 (76.1) |
| HAT titre median (IQR) | 0 (20) | 0 (0) | 0 (0) | 0 (0) |
Abbreviation: IQR, interquartile range.