Table 3.
Self-Isolation | Contact tracing | Non-HH contacts who are potentially traceable (%) | Cases who have R>1 (%) | Reff | Mean reduction in Reff | |
---|---|---|---|---|---|---|
No control | No | No | NA | 50% | 2·6 | 0% |
Self-isolation within home | Yes | No | NA | 40% | 1·8 | 29% |
Self-isolation outside home | Yes | NA | NA | 37% | 1·7 | 35% |
Self-isolation plus HHQ | Yes | HH | NA | 35% | 1·6 | 37% |
Self-isolation plus HHQ plus work or school contact tracing | Yes | HH and work or school | 100% | 27% | 1·2 | 53% |
Self-isolation plus HHQ plus manual contact tracing of acquaintances | Yes | All | 90% school, 79% work, and 52% other | 26% | 1·1 | 57% |
Self-isolation plus HHQ plus manual contact tracing of all contacts | Yes | All | 100% | 21% | 0·94 | 64% |
Self-isolation plus HHQ plus app-based tracing | Yes | All | 53% | 30% | 1·4 | 47% |
Self-isolation plus HHQ plus manual contact tracing of acquaintances plus app-based tracing | Yes | All | 90% school, 79% work, and 52% other with manual tracing; 53% with app tracing | 23% | 1 | 61% |
Self-isolation plus HHQ plus manual contact tracing of acquaintances plus limit to four daily contacts with other individuals | Yes | All | 90% school, 79% work, and 52% other | 21% | 0·93 | 64% |
Self-isolation plus HHQ plus manual contact tracing of acquaintances plus app-based tracing plus limit to four daily contacts with other individuals | Yes | All | 90% school, 79% work, and 52% other with manual tracing; 53% with app tracing | 20% | 0·87 | 66% |
Mass testing of 5% of population per week | No | NA | NA | 49% | 2·5 | 2% |
Results from 20 000 simulated setting-specific secondary transmissions, assuming a secondary attack rate of 20% among household contacts and 6% among other contacts. Results under the assumption of some workplace restrictions remaining in place are shown in table 4. Estimates are shown to two significant figures. HH=household. HHQ=household quarantine. NA=not applicable. Reff=effective reproduction number.