Table 2.
Immunogenicity responses after BNT162b2 vaccination in healthy children 6 months to under 5 years of age with history of COVID-19 during Omicron-predominant period and in children without history of COVID-19.
| Immunogenicity outcomes | Group A | Group B | COVID-naïve |
|---|---|---|---|
| pVNT-BA.2.75 (ID50) | |||
| - Post the 1st dose, GM (95% CI) | 553 (338–906) |
1383 (1100–1742) |
– |
| - Post the 2nd dose, GM (95% CI) | 753 (516–1098) |
1419 (1104–1823) |
38 (19–78) |
| - Post the 3rd dose, GM (95% CI) | – | – | 158 (98–255) |
| pVNT-BA.4/5 (ID50) | |||
| - Baseline, GM (95% CI) | 176 (122–252) |
235 (165–336) |
– |
| - Post the 1st dose, GM (95% CI) | 1936 (1402–2673) |
2627 (2048–3367) |
– |
| - Post the 2nd dose, GM (95% CI) | 1885 (1414–2512) |
2056 (1546–2735) |
28 (13–60) |
| - Post the 3rd dose, GM (95% CI) | – | – | 59 (31–114) |
| sVNT-BA.4/5 (%inhibition) | |||
| - Baseline, GM (95% CI) | 40.0 (30.4–52.7) |
37.9 (26.7–53.9) |
0.6 (0.2–1.7) |
| - Post the 1st dose, GM (95% CI) | 97.1 (94.3–99.9) |
98.7 (97.1–100.3) |
– |
| - Post the 2nd dose, GM (95% CI) | 89.9 (80.2–100.8) |
97.4 (95.5––99.3) |
13.2 (7.2–24.4) |
| - Post the 3rd dose, GM (95% CI) | – | – | 32.9 (23.6–45.9) |
| Anti-S-RBD IgG-BA.4/5 (AU/ml) | |||
| - Baseline, GM (95% CI) | 46 (38–55) |
53 (42–69) |
29 (24–34) |
| - Post the 1st dose, GM (95% CI) | 252 (203–312) |
312 (252–385) |
– |
| - Post the 2nd dose, GM (95% CI) | 248 (204–302) |
283 (232–346) |
45 (37–56) |
| - Post the 3rd dose, GM (95% CI) | – | – | 135 (112–162) |
Anti-S-RBD IgG-BA.4/5: Anti-spike-receptor-binding-domain of SARS-CoV-2 Omicron sublineage BA.4/5 immunoglobulin G; AU: arbitrary unit; GM: Geometric mean; Group A: Past COVID-19 for 3–6 months; Group B: Past COVID-19 for > 6 months; ID50: Neutralization dilution for 50% pseudovirus inhibition; pVNT-BA.2.75: Pseudovirus neutralization test against SARS-CoV-2 Omicron sublineage BA.2.75; pVNT-BA.4/5: Pseudovirus neutralization test against SARS-CoV-2 Omicron sublineage BA.4/5; sVNT-BA.4/5: Surrogate virus neutralization test against SARS-CoV-2 Omicron sublineage BA.4/5.