RADT (nasal) | Positive | Results, no. of participants | Invalid | Clinical performance of RADTs | Specificity, % (95% CI) | ||
---|---|---|---|---|---|---|---|
PCR (gargle) | Sensitivity, % (95% CI) | ||||||
Negative | Equivocal or weak positive | Excluding equivocal or weak positive | Including equivocal or weak positive | ||||
Asymptomatic students* | |||||||
Positive | 7 | 1 | 0 | 0 | n = 17 41.2 (21.6–64.0) | n = 26 26.9 (13.7–46.1) | 100§ (99.9–100) |
Negative | 10 | 5549 | 9 | 7 | |||
Invalid | 0 | 0 | 0 | 0 | |||
Asymptomatic students considered exposed contacts of positive index cases† | |||||||
Positive | 4 | 6 | 0 | 0 | n = 14 28.6 (8.4–58.1) | n = 15 26.7 (7.8–55.1) | 99.6 (99.1–99.9) |
Negative | 10 | 1470 | 1 | 0 | |||
Invalid | 0 | 0 | 0 | 0 | |||
Symptomatic students‡ | |||||||
Positive | 10 | 0 | 0 | 0 | 83.3 (51.6–97.9) | NA | 100.0 (98.4–100.0) |
Negative | 2 | 223 | 0 | 0 | |||
Invalid | 0 | 0 | 0 | 0 | |||
Asymptomatic staff members | |||||||
Positive | 0 | 1 | 0 | 0 | NA | NA | 99.9 (99.3–100.0) |
Negative | 0 | 775 | 0 | 2 | |||
Invalid | 0 | 0 | 0 | 0 | |||
Asymptomatic staff members considered exposed contacts of positive index cases | |||||||
Positive | 0 | 0 | 0 | 0 | NA | NA | 100.0 (94.1–100.0) |
Negative | 0 | 61 | 0 | 0 | |||
Invalid | 0 | 0 | 0 | 0 | |||
Symptomatic staff members | |||||||
Positive | 1 | 0 | 0 | 0 | 50.0 (1.3–98.7) | NA | 100.0 (94.3–100.0) |
Negative | 1 | 62 | 0 | 0 | |||
Invalid | 0 | 0 | 0 | 0 |
Note: CI = confidence interval, NA = not applicable, PCR = polymerase chain reaction, RADT = rapid antigen detection test.
↵* Prevalence of SARS-CoV-2 infection, based on PCR results (including equivocal and weakly positive results): 0.30% (95% CI 0.18%–0.49%).
↵† Prevalence of SARS-CoV-2 infection, based on PCR results (including equivocal and weakly positive results): 0.7% (95% CI 0.5%–1.6%).
↵‡ Prevalence of SARS-CoV-2 infection, based on PCR results (including equivocal and weakly positive results): 5.1% (95% CI 2.65%–8.71%).
↵§ The specificity of RADT in asymptomatic students was 99.98% when adjusted to 2 decimal places.