INTRODUCTION
METHODS
RESULTS
Base case | Higher prevalence of active infection | Better test specificity | Better test sensitivity and specificity | |
---|---|---|---|---|
Model parameters | • Prevalence of active infection: 1% • Test sensitivity, specificity: 90%, 95% • Reproduction number: 0.9 (0.1 after positive test) • Contacts per case: 5 | • Prevalence of active infection: 2.5% • Test sensitivity, specificity: 90%, 95% • Reproduction number: 0.9 (0.1 after positive test) • Contacts per case: 5 | • Prevalence of active infection: 1% • Test sensitivity, specificity: 90%, 99% • Reproduction number: 0.9 (0.1 after positive test) • Contacts per case: 5 | • Prevalence of active infection: 1% • Test sensitivity, specificity: 99%, 99% • Reproduction number: 0.9 (0.1 after positive test) • Contacts per case: 5 |
Results of testing | • True positive: 9000 (0.9%) • False positive: 49,500 (5.0%) • True negative: 940,500 (94.1%) • False negative: 1000 (0.1%) | • True positive: 22,500 (2.3%) • False positive: 48,750 (4.9%) • True negative: 926,250 (92.6%) • False negative: 2500 (0.3%) | • True positive: 9000 (0.9%) • False positive: 9900 (1.0%) • True negative: 980,100 (98.0%) • False negative: 1000 (0.1%) | • True positive: 9900 (1.0%) • False positive: 9900 (1.0%) • True negative: 980,100 (98.0%) • False negative: 100 (0.01%) |
Transmission chain of infection if testing | • From 9000 true positives: 9000 new cases • From 1000 false negatives: 9000 new cases | • From 22,500 true positives: 22,500 new cases • From 2500 false negatives: 22,500 new cases | • From 9000 true positives: 9000 new cases • From 1000 false negatives: 9000 new cases | • From 9900 true positives: 9900 new cases • From 100 false negatives: 900 new cases |
Transmission chain of infection if no testing | • From 10,000 infected individuals: 90,000 new cases | • From 25,000 infected individuals: 225,000 new cases | • From 10,000 infected individuals: 90,000 new cases | • From 10,000 infected individuals: 90,000 new cases |
Isolation and quarantine due to testing | • Isolation: 58,500 positive test results • Quarantine: 292,500 contacts | • Isolation: 71,250 positive test results • Quarantine: 356,250 contacts | • Isolation: 18,900 positive test results • Quarantine: 94,500 contacts | • Isolation: 19,800 positive test results • Quarantine: 99,000 contacts |
Overall effect of testing | • 72,000 fewer infections • 351,000 people isolated or quarantined • 4.9 number of people needed to isolate or quarantine (NNIQ) per infection prevented | • 180,000 fewer infections • 427,500 people isolated or quarantined • 2.4 NNIQ | • 72,000 fewer infections • 113,400 people isolated or quarantined • 1.6 NNIQ | • 79,200 fewer infections • 118,800 people isolated or quarantined • 1.5 NNIQ |