Table I.
Model Parameter Distributions and Sources
| Input | Definition [Unit] | Distribution | Mean [0.025; 0.5; 0.975 Quantiles] | Reference |
|---|---|---|---|---|
| Inputs Associated with Food Employees in the Restrooms | ||||
| VRest | Volume of the restrooms [m3] | cste(12.1) | – | 27 |
| nD | Number of defecations per shift on day 0 of sickness, divided by 2 each day while sick | Poisson(4.5) | 4.5 [1; 4; 9] | 24 |
| Pvomit | Probability that the sick food employee vomits | cste(0.72) | 10 | |
| nV | Number of vomit events per shift minus 1 each day while sick | cste(3) | – | 57 |
| nU | Number of restroom visits to urinate per shift | cste(2) | – | Assumed |
| mH | Mass of feces on hands after defecation [log10 g] | BetaPert(min=−8;mode=−3;max=−1 | −3.5 [−6.17; −3.38; −1.44] | 58, 59 |
| SH | Hand surface [m2] | cste(0.01) | – | 19 |
| VH | Volume of vomit on hands after vomiting events [mL] | cste(10) | – | Assuming 1 mm of vomit on all hand surface SH |
| NoVv | Norovirus concentration in vomit [log10 GEC NoV/mL] | BetaPert(3; 4.5; 7 | 4.67 [3.37; 4.62; 6.16] | 43 |
| NoVsh | Shedding level of food employee [log10 GEC NoV/g] | BetaPert(4; 8; 10 | 7.67 [5.40; 7.74; 9.52] | 9, 60, 61 |
| Dsh | Time to 1 log10 reduction of NoVs in shedding food employees [minutes] (eq. one log10decrease per week) | cste(10,080) | – | 9, 60, 61 |
| TrEnv, d | Aerosol contamination during diarrhea events [NoV/m3] | lognormal(7.6820;0.468) | 2,420 [867; 2,168;5,425] | 27 |
| TrEnv,V | Aerosol contamination during vomit events [GEC Nov/m3] | lognormal(7.6820;0.468)+1,100 | 3,520 [1,967; 3,268; 6,525] | 27, 28 |
| ds | Symptom duration [minutes] | gamma(scale=1.508; rate=0.000513) | 2,940 [218; 2,321; 9,140] (eq. 49 [4, 39, 152] hours) | 24 |
| PWash;H;Rest | Probability of washing hands in the restrooms (vomit, defecate, urinate) | cste(1;0.9; 0.65) | – | 17 |
| Inputs Associated with Food Employees Characteristics and Behavior | ||||
| nHwash;NFH | Number of handwashings per shift for nonfood handling employees | cste(4) | – | Assumed |
| PShedders | Probability of asymptomatic shedders | cste(0.15) | – | 23 |
| Pwear_gloves | Probability of wearing gloves during food preparation (0; .5; .9; 1 of the time) | (0.336; 0.14; 0.12; 0.40) | – | 20 |
| Pchange_gloves | Probability of changing gloves when engaging in food preparation | cste(0.37) | 22 | |
| Pwash;H | Probability of washing hands when engaging in food preparation | cste(0.41) | 22 | |
| Pwash;H | Probability of washing hands while changing gloves | cste(0.30) | 22 | |
| Inputs Associated with Transfer of Norovirus from Surface 1 to Surface 2 (Tr1;2) | ||||
| TrH;S | Norovirus transferred from hand to surface | inv.logit(normal(−3.82,ResTrans)) | 0.02 [4.61×10−4; 0.02; 0.51] | Meta‐analysis: 51, 52, 62, 63, 64, 65, 66, 67, 68, 69 |
| TrS;H | Norovirus transferred from surface to hand | inv.logit(normal (0.11,ResTrans)) | 0.53 [2.30×10−2; 0.53; 0.98] | |
| TrG;S | Norovirus transferred from glove to surface | inv.logit(normal (−2.14,ResTrans)) | 0.11 [2.47×10−3; 0.11; 0.85] | |
| TrS;G | Norovirus transferred from surface to glove | inv.logit(normal (−1.34,ResTrans)) | 0.21 [5.48×10−3; 0.21; 0.93] | |
| TrF;H | Norovirus transferred from food (nonmeat) to hand | inv.logit(normal (−3.86,ResTrans)) | 0.02 [4.43×10−4; 0.02; 0.50] | |
| TrH;F | Norovirus transferred from hand to food (nonmeat) | inv.logit(normal (−2.95,ResTrans)) | 0.05 [1.10×10−3; 0.05; 0.71] | |
| TrFm;H | Norovirus transferred from food (meat) to hand | inv.logit(normal (−2.62,ResTrans)) | 0.07 [1.53×10−3; 0.07; 0.78] | |
| TrH;Fm | Norovirus transferred from hand to food (meat) | inv.logit(normal (−0.034,ResTrans)) | 0.49 [0.02; 0.49; 0.98] | |
| TrF;G | Norovirus transferred from food (nonmeat) to glove | inv.logit(normal (0.90,ResTrans)) | 0.71 [0.05; 0.71; 0.99] | |
| TrG;F | Norovirus transferred from glove to food (nonmeat) | inv.logit(normal (−0.82,ResTrans)) | 0.31 [0.01; 0.31; 0.95] | |
| TrFm;G | Norovirus transferred from food (meat) to glove | inv.logit(normal (−0.13,ResTrans)) | 0.47 [0.02; 0.47; 0.98] | |
| TrG;Fm | Norovirus transferred from glove to food (meat) | inv.logit(normal (−0.29,ResTrans)) | 0.43 [0.02; 0.43; 0.97] | |
| TrF;S | Norovirus transferred from food (nonmeat) to surface | inv.logit(normal (−2.82,ResTrans)) | 0.06 [1.25×10−3; 0.06; 0.74] | |
| TrS;F | Norovirus transferred from surface to food (nonmeat) | inv.logit(normal (0.87,ResTrans)) | 0.70 [0.05; 0.70; 0.99] | |
| TrFm;S | Norovirus transferred from food (meat) to surface | inv.logit(normal (−0.94,ResTrans)) | 0.28 [0.01; 0.28; 0.95] | |
| TrS;Fm | Norovirus transferred from surface to food (meat) | inv.logit(normal (4.45,ResTrans)) | 0.99 [0.64; 0.99; 1.00] | |
| TrH;G | Norovirus transferred from hand to glove | inv.logit(normal (−2.78,ResTrans)) | 0.06 [1.30×10−3; 0.06; 0.75] | |
| ResTrans | Residuals of the meta‐analysis for transfer | cste(1.97) | – | |
| Meta‐analysis: | ||||
| DWH | Handwashing efficiency [log10 NoV] | BetaPert(0.17;0.45;6; shape=4) | 1.33 [0.23; 1.13; 3.47] | 55, 56, 58, 62, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81 |
| Inputs Associated with Survival of Norovirus on Surfaces | ||||
| DH | Time to 1 log reduction of GEC NoV on hands [minutes] | lognormal(6.50;ResSurv) | 1,154 [85; 665; 5,208] (eq.: 19 [1, 11, 87] hours) | Meta‐analysis: 63, 64, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95 |
| DS | Time to 1 log reduction of GEC NoV on hard surface [minutes] | lognormal(10.17; ResSurv) | 45,309 [3,334; 26,108; 204,426] (eq.: 755 [56, 435,3407] hours) | |
| DG | Time to 1 log reduction of GEC NoV on gloves [minutes] | lognormal(11.02; ResSurv) | 106,006 [7,801; 61,083; 478,285] (eq.: 1,766 [130, 1,018,7,971] hours) | |
| DF | Time to 1 log reduction of GEC NoV on food [minutes] | lognormal(9.57; ResSurv) | 24,866 [1,829; 14,328; 112,191] (eq.: 414 [30, 238, 1,870] hours) | |
| ResSurv | Residuals of the meta‐analysis for survival | cste(1.05) | – | |
| Inputs Associated with Disinfection | ||||
| Pdis | Probability of using a type of disinfectant in store (quaternary ammonium; chlorine) | (0.6;0.4) | – | |
| DisS;QUAT | GEC NoV reduction due to disinfection of hard surfaces with quaternary ammonium | log10(inv.logit(norm(−3.44, ResDis)) | −1.51 [−4.55; −1.51; −0.01] | Meta‐analysis: 75, 76, 77, 78, 79, 85, 93, 94, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105 |
| DisS;QUAT | GEC NoV reduction due to disinfection of hard surfaces with chlorine | log10(inv.logit(norm(−6.02, ResDis)) | −2.61 [−5.67; −2.61; −0.13] | |
| DisS;QUAT | GEC NoV reduction due to disinfection of hands with quaternary ammonium | log10(inv.logit(norm(−6.16, ResDis)) | −2.67 [−5.73; −2.67; −0.15] | |
| DisS;QUAT | GEC NoV reduction due to disinfection of hands with chlorine | log10(inv.logit(norm(−8.74, ResDis)) | −3.80 [−6.85; −3.80; −0.81] | |
| ResDis | Residuals of the meta‐analysis for disinfection | cste(3.59) | ||
Cste: constant; BetaPert: betapert distribution with shape parameter 430; X ∼ lognormal(a, b) if ln(X) ∼ normal(mean=a, SD=b); inv.logit(x) = exp(x)/(1+exp(x)).