Scenarios on the impact of pandemic influenza: preparedness planningMarianne van Genugten, Marie-Louise Heijnen, Hans Jager

Pandemic influenza | Genugten, Heijnen en Jager

Pandemic influenza?

• Influenza viruses changes slightly and frequently over time (antigenic drift)

• In some years the virus changes dramatically (antigenic shift)

• Earlier pandemics

Pandemic influenza | Genugten, Heijnen en Jager

Pandemic plan

• Another influenza pandemic is inevitable• High morbidity and mortality

Influenza pandemic planThe Dutch Ministry on Health, Welfare and sports

has designed a national plan in order to minimise the effects of pandemic influenza

Pandemic influenza | Genugten, Heijnen en Jager

Question

What is the expected number of of hospitalisations and deaths during an influenza pandemic?

1) What are options for intervention? Building-up of stocks (national level)

2) Number of hospital beds needed versus available. Contingency planning (local level)

Pandemic influenza | Genugten, Heijnen en Jager

Method

Many uncertainties Scenario-analysis

• model and data• expert consultation

– assumptions– scenario’s

Pandemic influenza | Genugten, Heijnen en Jager

v a c c in e c ov e r ag e a nd e ffic a cy

a tta c k r a te

h o sp ita lisa tio n r a ted e a th r a te

N u m b er ofh osp ita lisations

N u m b er ofd eaths

n u m b er of p ersonsw ith

in flu en za lik e illn ess

p op u lationat risk

p op u lation byh igh risk and

low risk

Model

Pandemic influenza | Genugten, Heijnen en Jager

Data need

• Population by risk • Age-specific attack, hospitalisation and

death rates – including excess

• Efficacy

Pandemic influenza | Genugten, Heijnen en Jager

Main assumptions

pandemic influenza ‘usual’ epidemic influenza

• age-specific hospitalisation, death and attack rates as in earlier epidemics

• basic care

(sensitivity analysis on age-specific rates)

Pandemic influenza | Genugten, Heijnen en Jager

Scenarios

• Non intervention • No influenza vaccine available and

pneumococcal vaccination of risk groups • No influenza vaccine available and

therapeutic use of antivirals for each person with influenza like illness

• Influenza vaccine available

Pandemic influenza | Genugten, Heijnen en Jager

1.915819

3.395

1.347

4.040

10.186

0

3.000

6.000

9.000

12.000

number of hospitalisations number of deaths

epidemic

pandemic of 10%

pandemic of 30%

Number of hospitalisations and deaths

Pandemic influenza | Genugten, Heijnen en Jager

2,78

4,693,59

15,62

5.093 (50%)

6.218 (61%)

6.339 (62%)

2.618 (26%)

0

5

10

15

20

25

pneumococcal vaccinationmedical risk groups

therapeutic use of antivirals influenza vaccination medicalrisk groups and health care

workers

influenza vaccination totalpopulation

req

uir

ed d

oses

/pre

scri

pti

ons

(mill

ion

s)

-

1.000

2.000

3.000

4.000

5.000

6.000

7.000

avoi

ded

nu

mb

er o

f h

osp

ital

isat

ion

s

Required doses/prescriptions

Avoided hospitalisations

Result 1: Avoided number of hospitalisations / required doses

Pandemic influenza | Genugten, Heijnen en Jager

Result 2: Hospital beds needed/available

Non intervention scenario– duration 6 weeks– length of hospital stay 8-14 days

6.000-8.500 beds needed

Total number of beds 55.000

Beds available depends on occupancy rate and nursing staff available

Pandemic influenza | Genugten, Heijnen en Jager

Preparedness planning

RIVM policy makers

Message policy makers ‘flu’ can be seriousminister of Health (national level)contingency planners (local level)

Pandemic influenza | Genugten, Heijnen en Jager

Conclusions

Scenario-analysis supports decision makers and contingency planners on national and local level

Insight in• the number of hospitalisations and deaths• comparison of intervention options • the crucial model parameters