Table 5. Base-case analysis using a deterministic model and a probabilistic model in an economic evaluation of wastewater surveillance combined with clinical COVID-19 screening tests, Japan*.
| Incidence† | Option 1 |
Option 2 |
Relative value of option 2 |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Cost | Benefit | ROI 1‡ | Cost | Benefit | ROI 2‡ | Inc. cost§ | Inc. benefit¶ | Rel. ROI# | |||
| 10 | |||||||||||
| DA | $67.04 | $1.39 | 0.021 | $53.60 | $1.14 | 0.021 | –$13.44 | –$0.25 | 54 | ||
| Mean PA
(95% PCI) |
$70.03 ($49.85–$90.25) |
$1.43 ($0.42–$2.85) |
0.021 (0.006–0.043) |
|
$50.68 ($25.27–$90.23) |
$0.97 ($0.19–$2.04) |
0.021 (0.004–0.051) |
|
–$19.35
(–$54.48 to $24.31) |
–$0.46
(–$1.20 to $0.08) |
45
(−194 to 387) |
| 100 | |||||||||||
| DA | $67.05 | $14.09 | 0.21 | $53.61 | $11.94 | 0.22 | –$13.43 | –$2.15 | 6.25 | ||
| Mean PA
(95% PCI) |
$68.54 ($48.77–$88.86) |
$14.75 ($5.11–$28.35) |
0.22
(0.07–0.45) |
|
$50.86 ($24.95–$92.14) |
$10.37 ($3.03–$20.71) |
0.23 (0.05–0.60) |
|
–$17.68
(–$52.33 to $23.34) |
–$4.38
(–$11.35 to $1.31) |
5.74
(−24 to 37) |
| 1,000 | |||||||||||
| DA | $67.12 | $141.11 | 2.10 | $53.75 | $119.94 | 2.23 | –$13.37 | –$21.16 | 0.63 | ||
| Mean PA (95% PCI) | $69.50 ($48.76–$89.54) | $147.29 ($52.37– $279.00) | 2.17 (0.73–4.57) | $50.61 ($24.56–$89.89) | $104.58 ($30.91–$215.00) | 2.29 (0.55–5.59) | –$18.89 (–$52.28 to $23.15) | –$42.71 (–$110 to $8.65) | 0.34 (−2.14 to 3.71) | ||
*A probabilistic model to compare clinical tests only (option 1) to wastewater surveillance combined with clinical tests (option 2). If one option is cost-saving compared with its comparator, the option’s ROI is estimated to exceed 1. The comparator of options 1 and 2 is do-nothing. DA, deterministic model analysis; inc., incremental; PA, probabilistic model analysis with Monte Carlo simulations; PCI, probabilistic confidence interval; rel., relative; ROI, return on investment. †Disease incidence per day per 1 million residents in the area. ‡ROI is benefit divided by cost for each option. §Incremental cost is the cost of option 2 minus cost of option 1. A negative value of incremental cost indicates that option 2 has a lower cost or is cost-saving, compared with option 1. This could be interpreted as option 2’s relative benefit. ¶Incremental benefit is the benefit of option 2 minus benefit of option 1. A negative value of incremental benefit indicates that option 2 has a lower benefit compared with option 1, which could be interpreted as option 2’s relative cost. #Relative ROI is incremental cost divided by incremental benefit.