Percentage of Ehteraz accuracy against WHO duration and distance criteria for COVID-19 contact and the categories of the contacts
| Number of contacts (%) N=5650 (100%) | |
| Contact distance/duration according to WHO criteria (contact distance within 1 metre of a case for >15 min) | |
| Matched | 3000 (53.1%) |
| Not matched | 2650 (46.9%) |
| Categories of the contacts of 219 index cases | |
| Index also in swab collection | 43 (19.6% of index cases) |
| Contact also in swab collection | 319 (5.7% of contact cases) |
| Contacts same residential address | 339 (6.0%) |
| Contacts same company/guardian | 435 (7.7%) |
| Contacts same employer | 270 (4.8%) |
| Contacts with at least one of the above three relations with index case | 677 (12.0%) |
| Contacts with no know relations to index case | 4973 (88.0%) |