Table 2.
Virological results of SARS-CoV-2 infection in the children included in the study
| Overall (N = 1009) | Symptomatic (n = 493) | Asymptomatic (n = 516) | p-value | |
|---|---|---|---|---|
| Positive RT-qPCR, n (%) | 46 (4.6) | 35 (7.3) | 11 (2.1) | <0.001 |
| Ct value of nucleocapsid target, mean (SD) | 24.0 (7.3) | 22.2 (5.8) | 29.8 (8.5) | 0.002 |
| Ct value of polymerase target, mean (SD) | 24.2 (6.6) | 22.7 (5.5) | 29.2 (8.0) | 0.005 |
| Ct-value category, n (%) | 0.034 | |||
| Strong positive (Ct < 23) | 26 (56.5) | 23 (65.7) | 3 (27.3) | |
| Positive (23 ≤ Ct < 33) | 13 (28.3) | 9 (25.7) | 4 (36.4) | |
| Low positive (Ct ≥ 33) | 7 (15.2) | 3 (8.6) | 4 (36.4) | |
| Positive AgPOCT, n (%) | 33 (3.3) | 30 (6.1) | 3 (0.6) | <0.001 |
| Ct value of nucleocapsid target, mean (SD) | 19.9 (3.6) | 20.1 (3.7) | 17.9 (4.3) | |
| Ct value of polymerase target, mean (SD) | 20.6 (3.3) | 20.7 (3.3) | 18.9 (1.7) | |
| Negative AgPOCT, n (%) | 14 (1.4) | 6 (42.9) | 8 (57.1) | |
| Ct value of nucleocapsid target, mean (SD) | 33.3 (4.1) | 32.1 (4.6) | 34.2 (4.6) | |
| Ct value of polymerase target, mean (SD) | 33.0 (3.6) | 32.3 (3.2) | 33.6 (1.2) | |
| Concordance between RT-qPCR and AgPOCT, n (%) | <0.001 | |||
| False negative | 14 (1.4) | 6 (1.3) | 8 (1.6) | |
| False positive | 1 (0.1) | 1 (0.2) | 0 (0) | |
| True negative | 943 (95.3) | 440 (92.4) | 501 (97.9) | |
| True positive | 32 (3.2) | 29 (6.1) | 3 (0.6) |
Symptomatic means the presence of a clinical picture compatible with SARS-CoV-2 infection, as described in the text. AgPOCT, antigen point-of-care test; Ct, cycle threshold; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2; SD, standard deviation.