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Table 2 Values for disease states and heath utilisation rates used in economic model. Mean and 95% confidence interval (CI) or proportions are given

From: Seasonal influenza vaccination in Kenya: an economic evaluation using dynamic transmission modelling

Item

Measure

Value

Distribution

Reference

Disease states

 Proportion of influenza cases that develop any clinical symptoms

Mean (95% CI)

0.669 (0.583–0.745)

Normal

[27]

 Proportion of influenza cases that develop upper respiratory tract symptoms/mild illness

Mean (95% CI)

0.588 (0.455–0.708)

Normal

[27]

 Proportion of influenza cases that develop lower respiratory tract symptoms/severe illness

Mean (95% CI)

0.210 (0.140–0.303)

Normal

[27]

Proportion of influenza cases with severe illness that die while hospitalised

< 1 year

Mean (95% CI)

0.0274 (0–0.0616)

Truncated normal

Influenza SARI surveillance dataset (2010–2018)

1–5 years

Mean (95% CI)

0.0091 (0–0.0322)

6–14 years

Mean (95% CI)

0.0108 (0–0.0902)

15–20 years

Mean (95% CI)

0 (0–0.1116)

20–49 years

Mean (95% CI)

0.0331 (0–0.0818)

  ≥ 50 years

Mean (95% CI)

0.1818 (0.0909–0.3080)

All ages

Mean (95% CI)

0.0200 (0.0035–0.0373)

Proportion of deaths due to a respiratory illness that occur in a health facility

  < 1 year

Mean (95% CI)

0.2794 (0.2451–0.3140)

Normal

Siaya health demographic and surveillance site dataset (2010–2016)

1–5 years

Mean (95% CI)

0.2899 (0.2471–0.3349)

6–14 years

Mean (95% CI)

0.4361 (0.3534–0.5278)

15–20 years

Mean (95% CI)

0.5250 (0.3750–0.6795)

20–49 years

Mean (95% CI)

0.5067 (0.4626–0.5525)

  ≥ 50 years

Mean (95% CI)

0.2715 (0.2421–0.3012)

All ages

Mean (95% CI)

0.3287 (0.3106–0.3474)

Health care utilisation events

 Proportion of symptomatic influenza cases who attend outpatient clinic

0–5 years

Mean (95% CI)

0.475 (0.39–0.60)

Normal

[29]

6–12 years

Mean (95% CI)

0.118 (0.09–0.17)

13–17 years

Mean (95% CI)

0.088 (0.06–0.13)

18–24 years

Mean (95% CI)

0.035 (0.02–0.08)

25–44 years

Mean (95% CI)

0.034 (0.02–0.07)

45–64 years

Mean (95% CI)

0.027 (0.01–0.05)

   ≥ 65 years

Mean (95% CI)

0.036 (0.02–0.07)

 Proportion of symptomatic influenza cases who are hospitalised

0–5 years

Mean (95% CI)

0.0102 (0.0089–0.0117)

Normal

[29]

6–12 years

Mean (95% CI)

0.0007 (0.0006–0.0010)

13–17 years

Mean (95% CI)

0.0006 (0.0004–0.0011)

18–24 years

Mean (95% CI)

0.0008 (0.0006–0.0010)

25–44 years

Mean (95% CI)

0.0021 (0.0018–0.0024)

45–64 years

Mean (95% CI)

0.0026 (0.0020–0.0033)

   ≥ 65 years

Mean (95% CI)

0.0033 (0.0025–0.0044)

Proportion of outpatient influenza cases who purchased medication prior to clinic visit

Proportion

0.718

Fixed value

[30]

Proportion of hospitalised influenza cases who sought care after discharge from hospital

Proportion

0.105

Fixed value

[30]

Proportion of non-medically attended influenza cases where household members missed work due to illness*

Proportion

Not known

–

–

Proportion of outpatient influenza cases where household members missed work due to illness

Proportion

0.518

Fixed value

[30]

Proportion of hospitalised influenza cases where household members missed work due to illness

Proportion

0.848

Fixed value

[30]

Proportion of non-medically attended influenza cases where household members paid for childcare during illness*

Proportion

Not known

–

–

Proportion of outpatient influenza cases where household members paid for childcare during illness

Proportion

0.18

Fixed value

[30]

Proportion of hospitalised influenza cases where household members paid for childcare during illness

Proportion

0.29

Fixed value

[30]

  1. *These items were not included in the model as the values were unknown and difficult to estimate in the case of non-medically attended illness