Table 2.
Diagnostic accuracy parameters for the saliva and nasal Ag-RDTs. Values are percentages (95% confidence interval) unless stated otherwise
| Analysis | No | Prevalencea [%] | Sensitivity [%] (95%CI) |
Specificity [%] (95%CI) |
PPV [%] (95%CI) |
NPV [%] (95%CI) |
|---|---|---|---|---|---|---|
| COVID-19 antigen rapid test (oral fluid) for self-testing (Hangzhou AllTest Biotech Co., Ltd.) | ||||||
| Primary analysis | 2803 | 6.5 | 46.7 (39.3 to 54.2) | 99.0 (98.5 to 99.4) | 76.6 (67.6 to 84.1) | 96.4 (95.6 to 97.1) |
| Secondary (stratified) analysis | ||||||
| Infectiousness viral load cut-offb,$ | 2788 | 5.1 | 54.9 (46.4 to 63.3) | 98.8 (98.3 to 99.2) | 70.9 (61.5 to 79.2) | 97.6 (97.0 to 98.2) |
| Symptoms present at samplingc | ||||||
| Yes | 2306 | 6.5 | 51.0 (42.7 to 59.2) | 98.8 (98.3 to 99.2) | 75.5 (66.0 to 83.5) | 96.6 (95.8 to 97.4) |
| No | 484 | 6.4 | 25.8 (11.9 to 44.6) | 99.8 (98.8 to 100) | 88.9 (51.8 to 99.7) | 95.2 (92.8 to 96.9) |
| Vaccinated (at least one)d | ||||||
| Yes | 2390 | 4.8 | 47.0 (37.6 to 56.5) | 99.0 (98.5 to 99.4) | 71.1 (59.5 to 80.9) | 97.4 (96.6 to 98.0) |
| No | 404 | 16.6 | 46.3 (34.0 to 58.9) | 98.8 (97.0 to 99.7) | 88.6 (73.3 to 96.8) | 90.2 (86.7 to 93.1) |
| Previous SARS-CoV-2 infectione | ||||||
| Yes | 366 | 5.5 | 20.0 (5.7 to 43.7) | 99.1 (97.5 to 99.8) | 57.1 (18.4 to 90.1) | 95.5 (92.9 to 97.4) |
| No | 2427 | 6.7 | 50.0 (42.1 to 57.9) | 99.0 (98.5 to 99.4) | 77.9 (68.7 to 85.4) | 96.5 (95.7 to 97.2) |
| Sexf | ||||||
| Female | 1711 | 6.3 | 38.0 (28.8 to 47.8) | 99.2 (98.6 to 99.6) | 75.9 (62.4 to 86.5) | 96.0 (94.9 to 96.9) |
| Male | 1081 | 6.8 | 60.3 (48.1 to 71.5) | 98.7 (97.8 to 99.3) | 77.2 (64.2 to 87.3) | 97.2 (96.0 to 98.1) |
| Age [years]g | ||||||
| ≥ 16 to ≤ 40 | 1450 | 6.3 | 41.3 (31.1 to 52.1) | 98.9 (98.2 to 99.4) | 71.7 (57.7 to 83.2) | 96.1 (95.0 to 97.1) |
| > 40 to ≤ 65 | 1135 | 6.3 | 50.0 (38.0 to 62.0) | 99.2 (98.4 to 99.6) | 80.0 (65.4 to 90.4) | 96.7 (95.5 to 97.7) |
| > 65 | 208 | 8.2 | 64.7 (38.3 to 85.8) | 99.0 (96.3 to 99.9) | 84.6 (54.6 to 98.1) | 96.9 (93.4 to 98.9) |
| SD Biosensor SARS-CoV-2 Rapid Antigen Test Nasal by Roche Diagnostics (‘Nasal’), | ||||||
| Primary analysis | 2819 | 6.4 | 68.9 (61.6 to 75.6) | 99.5 (99.2 to 99.8) | 91.2 (85.1 to 95.4) | 97.9 (97.3 to 98.4) |
| Secondary (stratified) analysis | ||||||
| Infectiousness viral load cut-offb,$ | 2804 | 5.1 | 83.9 (76.9 to 89.5) | 99.5 (99.2 to 99.7) | 90.2 (83.9 to 94.7) | 99.1 (98.7 to 99.5) |
| Symptoms present at samplingc | ||||||
| Yes | 2319 | 6.4 | 78.5 (71.1 to 84.8) | 99.5 (99.2 to 99.8) | 92.1 (86.0 to 96.2) | 98.5 (97.9 to 99.0) |
| No | 487 | 6.4 | 22.6 (9.6 to 41.1) | 99.6 (98.4 to 99.9) | 77.8 (40.0 to 97.2) | 95.0 (92.6 to 96.8) |
| Vaccinated (at least one)d | ||||||
| Yes | 2389 | 4.5 | 70.1 (60.5 to 78.6) | 99.6 (99.2 to 99.8) | 88.2 (79.4 to 94.2) | 98.6 (98.0 to 99.0) |
| No | 421 | 17.3 | 67.1 (55.1 to 77.7) | 99.4 (97.9 to 99.9) | 96.1 (86.5 to 99.5) | 93.5 (90.5 to 95.8) |
| Previous SARS-CoV-2 infectione | ||||||
| Yes | 372 | 5.1 | 36.8 (16.3 to 61.6) | 99.2 (97.5 to 99.8) | 70.0 (34.8 to 93.3) | 96.7 (94.3 to 98.3) |
| No | 2437 | 6.6 | 72.7 (65.1 to 79.4) | 99.6 (99.3 to 99.8) | 92.9 (86.9 to 96.7) | 98.1 (97.5 to 98.6) |
| Sexf | ||||||
| Female | 1717 | 6.2 | 68.9 (59.1 to 77.5) | 99.6 (99.1 to 99.8) | 91.2 (82.8 to 96.4) | 98.0 (97.2 to 98.6) |
| Male | 1090 | 6.7 | 69.9 (58.0 to 80.1) | 99.5 (98.9 to 99.8) | 91.1 (80.4 to 97.0) | 97.9 (96.8 to 98.7) |
| Age [years]g | ||||||
| 16 to ≤ 40 | 1463 | 6.4 | 66.7 (56.1 to 76.1) | 99.5 (99.0 to 99.8) | 89.9 (80.2 to 95.8) | 97.8 (96.9 to 98.5) |
| > 40 to ≤ 65 | 1139 | 6.1 | 72.9 (60.9 to 82.8) | 99.6 (99.0 to 99.9) | 92.7 (82.4 to 98.0) | 98.2 (97.3 to 98.9) |
| > 65 | 206 | 7.8 | 68.8 (41.3 to 89.0) | 99.5 (97.1 to 100) | 91.7 (61.5 to 99.8) | 97.4 (94.1 to 99.2) |
PPV positive predictive value, NPV negative predictive value
aSARS-CoV-2 infection based on molecular test result
bViral load cut-off for infectiousness, defined as viral load above which 95% of people with a positive RT-PCR test result had a positive viral culture6, was 5.2 log10 SARS-CoV-2 E-gene copies/mL
cSymptoms not available for 13, and 13 participants, including 0, and 0 with a positive molecular test result, in those that had a saliva test result, and those that had a nasal test result, respectively
dCOVID-19 vaccination status not available from 9, and 9 participants, including 0, and 0 with a positive molecular test result in those with a saliva test result and nasal test result, respectively
ePrevious SARS-CoV-2 infection information not available from 10 and 10 participants, including 0 and 0 with a positive molecular test result, in those that had a saliva test result and those that had a nasal test result, respectively
fSex not available from 11 and 12 participants that had a saliva test result and that had a nasal test result, respectively
gAge was not available from 10 and 11 participants that had a saliva test result and that had a nasal test result, respectively
$Viral load unavailable for 15 individuals that had a saliva test result and 15 individuals that had a nasal test result