Background
Methods
Individual-centered model of influenza infection, illness, and health-care use
Parameter | Baseline values | Sources |
---|---|---|
Infectivity profiles
| Adapted from [13], and consistent (to a scale factor) with [10,15–21] | |
Latent period | 0.5 days | |
Peak | 2.5–3 days | |
Duration | <10 days | |
Relative susceptibility
| [5,13] | |
Children (0–18 years) | 1.15 | |
Adults (19–65 years) | 1 | |
Elderly (>65 years) | 1 | |
Proportion of asymptomatic individuals (children, adults, elderly people)
| 30% | [48]; also used in [6] |
Relative infectivity of asymptomatic individuals
| 50% | Assumption also used in [6] |
Community model
Place | Size | Graph | Assignment | Meetings |
---|---|---|---|---|
Households | 1 to 6 | Fully connected | D | |
Schools | ||||
Elementary | 5 classes; 20 children and 2 adults per class | Each class is modeled using a BA graph (m = 2); supplementary random links between individuals belonging to different classes. | Children living in the district | WD |
Secondary | 13 to 15 classes; 30 students and 3 teachers per class | Children and students are linked to teachers. | One college for 5 districts | WD |
Workplaces | 6 to 3000 according to Zipf distribution [49] | BA graph (m = 6) | 80% from the district; 20% from outside the district | WD |
Nursing homes | 45 elderly people, 50 employees per nursing home | BA graph (m = 6) | WD | |
District | All individuals | BA graph (m = 1) | WE |
Simulation process and empirical calibration
Results
Reference scenario
Outcomes | Outbreak
n = 114 | All simulations
n = 200 | |
---|---|---|---|
Mean | Minimum-Maximum | Mean | |
Infections | |||
Total
|
46.8
|
42.3–50.5
|
26.7
|
Children (0–18 years)
a
| 76.5 | 71.9–79.7 | 43.6 |
Adults (19–65 years)
a
| 39.9 | 34.8–44.0 | 22.8 |
Elderly (>65 years)
a
| 25.3 | 20.8–30.1 | 14.4 |
Physician visits | 31.2 | 28.0–33.7 | 17.8 |
Hospital admissions | 1.74 | 1.30–2.30 | 0.99 |
Deaths | 0.36 | 0.17–0.55 | 0.21 |
Lost workdays
b
| 137 | 118–150 | 78 |
Intervention scenarios
Outcomes | Outbreak; n = 106 | All simulations; n = 200 | |
---|---|---|---|
Mean | Minimum-Maximum | Mean | |
Infections | |||
Total
|
43.3
|
38.5–48.0
|
23.0
|
Children
a
| 72.5 | 67.9–76.4 | 38.4 |
Adults
a
| 36.5 | 30.6–41.8 | 19.3 |
Elderly
a
| 22.3 | 18.6–26.0 | 11.8 |
Physician visits | 28.0 | 24.3–31.2 | 14.9 |
Hospital admissions | 0.98 | 0.66–1.18 | 0.52 |
Deaths | 0.21 | 0.12 – 0.32 | 0.11 |
Lost workdays
b
| 125 | 107–141 | 66 |
Treatment units (doses)
c
| 243 | 215–269 | 129 |
Outcomes | Prophylaxis (Outbreak, n = 90) | Prophylaxis + treatment (Outbreak, n = 98) | ||
---|---|---|---|---|
Mean | Minimum-Maximum | Mean | Minimum-Maximum | |
Infections | ||||
Total
|
36.1
|
32.1–40.1
|
34.2
|
30.8–37.4
|
Children
a
| 61.8 | 57.0–66.2 | 58.5 | 53.1–64.5 |
Adults
a
| 30.2 | 25.6–35.0 | 28.8 | 24.2–33.4 |
Elderly
a
| 16.8 | 11.2–21.2 | 14.9 | 11.3–18.9 |
Physician visits | 23.8 | 21.8–27.0 | 22.2 | 19.6–24.8 |
Hospital admissions | 1.18 | 0.70–1.57 | 0.77 | 0.59–0.98 |
Deaths | 0.25 | 0.13–0.43 | 0.16 | 0.06–0.28 |
Lost workdays
b
| 106 | 94–122 | 100 | 85–116 |
Treatment units (doses)
c
| 196 | 179–210 | 393 | 356–435 |
Outcomes | Interval (days) | |||
---|---|---|---|---|
0 (Outbreak, n = 121) | 28 (Outbreak, n = 122) | |||
Mean | Minimum-Maximum | Mean | Minimum-Maximum | |
Infections | ||||
Total
|
4.2
|
0.5–15.7
|
36.1
|
2.0–46.9
|
Children
a
| 8.6 | 0.7–31.5 | 62.6 | 4.6–77.7 |
Adults
a
| 3.0 | 0.4–11.9 | 29.7 | 1.4–40.2 |
Elderly
a
| 1.6 | 0.0–5.8 | 18.1 | 0.5–27.8 |
Physician visits
b
| 1.6 | 0.0–10.3 | 23.9 | 1.3–31.2 |
Hospital admissions | 0.15 | 0.01–0.5 | 1.34 | 0.06–1.92 |
Deaths | 0.033 | 0–0.14 | 0.29 | 0.02–0.51 |
Lost workdays
c
| 11 | 1–44 | 103 | 5–137 |
Vaccination | 69.8 | 69–71 | 61.6 | 44–71 |
Outcomes | Closing schools (Outbreak, n = 111) | Closing schools and workplaces (Outbreak, n = 101) | ||
---|---|---|---|---|
Mean | Minimum-Maximum | Mean | Minimum-Maximum | |
Infections | ||||
Total
|
9.7
|
0.5–19.5
|
1.1
|
0.6–2.1
|
Children
a
| 10.3 | 1.6–23.1 | 2.0 | 0.6–3.8 |
Adults
a
| 9.9 | 0.6–23.7 | 0.8 | 0.4–1.5 |
Elderly
a
| 6.1 | 0.3–14.5 | 0.8 | 0.1–3.2 |
Physician visits | 6.4 | 0.6–14.1 | 0.7 | 0.4–1.4 |
Hospital admissions | 0.36 | 0.03–0.9 | 0.04 | 0.0–0.11 |
Deaths | 0.081 | 0–0.3 | 0.009 | 0.0 – 0.04 |
Lost workdays
b
| 324 | 80–464 | 1885 | 977–5484 |
Duration of closure (days) | 101 | 13–107 | 27 | 14–78 |