- Modeling data suggest that aggressive contact tracing and case isolation might contain >80% of new COVID-19 outbreaks within 3 months.
Why this matters
- At R 0 1.5, median estimate rapidly declined (
- Control probability declined as initial case numbers increased.
- At R 0 2.5, >80% of infected contacts needed tracing to achieve 90% control.
- At R 0 3.5, >90% of contacts needed tracing to achieve 90% control.
- Delay from symptom onset to isolation had greatest effect on outbreak control for all reproduction models.
- Mathematical modeling assessing effectiveness of isolation, contact tracing for COVID-19 disease outbreak containment in areas without widespread transmission: (1) initial case numbers, (2) reproduction number (R 0 ), (3) delay in symptom onset to isolation, (4) probability of contacts traced, (5) cases transmitted presymptom onset, (6) subclinical infections.
- Outbreaks considered contained if transmission ended within 12-16 weeks.
- Funding: National Institute for Health Research; others.
- Confounders (e.g., control measures) unaccounted for.
- Precision bias.