|
Epidemiology
|
|
Prevalence of current or recent SARS-CoV-2 infection (%) *
|
25
|
5
|
Assumption
|
|
Proportion amongst those tested who are in acute phase
|
0.5–1.00
|
0.5–1.00
|
Assumption
|
|
Of those in acute phase, number of infectious days remaining (days)
|
5–15
|
5–15
|
[16]
|
|
Case fatality rate amongst hospitalised COVID-19 patients
|
0.20–0.30
|
N/A
|
[7]
|
|
Case fatality reduction amongst COVID-19 patients on dexamethasone (1—risk ratio)
|
0.07–0.25
|
N/A
|
[7]
|
|
NAT performance
| |
|
NAT sensitivity (for current or recent SARS-CoV-2)
|
0.85–0.95
|
0.85–0.95
|
[17,18,19,20,21,22,23]
|
|
NAT specificity
|
0.99–1
|
0.99–1
|
[17,18,19,20]
|
|
NAT availability (proportion able to access NAT test)
|
0.1–1
|
0.1–1
|
Assumption
|
|
Cost per NAT test ($)
|
20–70
|
20–70
| |
|
NAT turnaround time (days)
|
1–10
|
5–15
|
[10], Expert consultation
|
|
Confirm Ag-RDT negative results with NAT
|
Y/N
|
Y/N
| |
|
Confirm Ag-RDT positive results with NAT **
|
Y/N
|
Y/N
| |
|
Isolate and initiate treatment (if indicated) whilst awaiting NAT result
|
Y
|
N
| |
|
Ag-RDT performance (assumed fixed)
| |
|
Ag-RDT sensitivity for current infection, relative to NAT (%, assumed only amongst acute cases)*
|
0.80
|
0.80
|
[14, 15]
|
|
Ag-RDT specificity, relative to NAT (%)*
|
0.98
|
0.98
|
[14, 15]
|
|
Cost per Ag-RDT test ($)
|
5
|
5
|
[14]
|
|
Clinical judgement and management
| |
|
Sensitivity of clinical judgement in absence of NAT
|
0.45–0.99
|
0.45–0.99
|
[24,25,26,27]
|
|
Specificity of clinical judgement in absence of NAT
|
0.20–0.70
|
0.20–0.50
|
[24,25,26,27]
|
|
Proportion of hospitalised patients with a negative COVID-19 test result (true and false negatives) that are initiated onto dexamethasone
|
0.05–0.15
|
N/A
|
Assumption
|
|
Duration of isolation (days)
|
10
|
10
|
[16]
|
|
Duration of dexamethasone treatment (days)
|
10
|
N/A
|
[7]
|
|
Cost of isolation per day ($)
|
50–350
|
N/A
|
[28,29,30]
|
|
Cost of dexamethasone per day ($)
|
0.13–3.5
|
N/A
|
[31]
|
