Table 6.
Virological and genomic evidence reported in 591 studies included in five systematic reviews of transmission of SARS-CoV-2. Key: Ct = cycle threshold; CPE = cytopathic effect.
| Review | Primary Studies | PCR Result (% of Studies) |
Ct (% of Studies) |
Ct < 25 (% of Studies) |
Attempted Viral Culture (% of Studies) |
CPE (% of Studies) |
Genome Sequencing (% of Studies) | Serial Viral Culture Positive (% of Studies) |
|---|---|---|---|---|---|---|---|---|
| Airborne Transmission [10] | 127 | 53 (79.1%) |
51 (40.2%) |
5 (3.9%) |
26 (20.4%) |
5 (3.7%) 1 |
6 (4.7%) |
3 (2.3%) 2 |
| Fomite Transmission [11] | 63 | 51 (81.0%) |
13 (20.6%) |
3 (4.8%) |
11 (17.5%) |
0 | 0 | 0 |
| Orofecal Transmission [9] | 77 | 46 (59.7%) |
22 (28.6%) |
7 (9.1%) |
6 (7.8%) |
1 (1.3%) 3 |
1 (1.3%) |
0 3 |
| Close Contact Transmission [12] | 258 | 163 (73.7%) |
26 (10.1%) |
6 (2.3%) |
4 (1.6%) |
2 (0.6%) |
18 (5.8%) |
2 (1.2%) |
| Vertical Transmission [13] | 66 | 66 (100%) |
9 (13.6%) |
2 (3.0%) |
0 | 0 | 1 (1.5%) |
0 |
| (% of primary studies) | 591 | 379 (64.1%) |
121 (20.5%) |
23 (3.9%) |
48 (8.1%) |
9 (1.5%) |
26 (4.4%) |
5 (0.85%) |
1 Some studies observed presumed virus-induced CPE. 2 Two studies detected other viruses, all studies had methodological limitations. 3 CPE did not show plaques and is not immunostained.