Table 6.
Comparison of COVID-19 antibody response between those who acquired COVID-19 infection (n = 29) or not (n = 70) after the second dose of vaccine in the cohort of those without detectable anti-spike antibody before vaccination (n = 99).
| COVID-19 Antibody | Time of Specimen Collection (Days) | |||||||
|---|---|---|---|---|---|---|---|---|
| Before the Second Dose | 60 Days after Second Dose | 150 Days after Second Dose | 270 Days after Second Dose | |||||
| Acquired COVID-19 Infection | Not Acquired COVID-19 Infection | Acquired COVID-19 Infection | Not Acquired COVID-19 Infection | Acquired COVID-19 Infection | Not Acquired COVID-19 Infection | Acquired COVID-19 Infection | Not Acquired COVID-19 Infection | |
| Anti-Spike antibody (U/mL) | 76.8 (23.4–200.4) |
36.2 (10.2–98.6) |
14,019 (4546–25,000) |
147.5 (85.4–387.7) |
2062 (139–4317) |
64.3 (37.4–154.3) |
2185 (1414–4611) |
1450 (128–12,885) |
| p value | 0.052 | <0.001 | <0.001 | 0.147 | ||||
| Neutralising antibody (%) | 18 (7.6–27.5) |
18.4 (5.8–32.9) |
86.9 (66.6–97) |
21 (5.3–65.5) |
79.3 (45–90.8) |
16.1 (2.8–64.8) |
67.7 (54–84.7) |
48.7 (12.6–85.8) |
| p value | 0.936 | <0.001 | 0.001 | 0.277 | ||||
Anti-spike antibody titre is expressed as U/mL and neutralising antibody is expressed as a percentage. The anti-spike antibody titre value ≥ 0.80 U/mL is considered positive. The specimens with calculated neutralisation ≥ 20% are considered positive for neutralising antibody. Data are expressed as median (interquartile range).