Influenza Surveillanceat IRID

Immunization and Respiratory Infections DivisionCentre for Infectious Disease Prevention & Control

Public Health Agency of Canada

Impact of InfluenzaIn Canada: • 10-25% of population affected yearly (higher

infection rates in children and elderly)• 70-75,000 hospitalizations• 6-7,000 deaths due to pneumonia and influenza• 500-1,500 deaths due to influenza

0

2000

4000

6000

8000

10000

12000

14000

1992

01

1993

01

1994

01

1995

01

1996

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1997

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1998

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1999

01Year & Month

P&I Morbidity

Canada’s National Influenza Surveillance Program

Primary Objectives : 1) Early detection and monitoring of influenza outbreaks

2) Provide timely and up-to-date reporting of influenza activity in Canada and abroad to professionals & public

3) Monitor circulating strains of influenza virus, including new sub-types

4) Contribute to the information for vaccine composition for following season

Influenza Surveillance

ILI ConsultationsSentinel Physicians

Laboratories Number of Influenza tests and positives

National Microbiology Laboratory

Strain Characterization

Provincial/Territorial Epidemiologists

Influenza activity levels (outbreaks etc)

Data Provider Indicator

Uses of Surveillance Data

• estimating disease impact – influenza-like illness clinic visits– influenza and pneumonia

hospitalizations and deaths– all cause mortality– other health and economic impacts

• monitoring viral evolution – identification of predominant strains– detection of new strains/subtypes

Influenza prevention and control policies

Vaccine composition program development and timing

Number of Influenza regions reporting widespread or localized activity

0

5

10

15

20

25

30

8-30

9-13

9-27

10-1

1

10-2

5

11-8

11-2

2

12-6

12-2

0

1-3

1-17

1-31

2-14

2-28

3-13

3-27

4-10

4-24 5-

8

5-22 6-

5

6-19 7-

3

7-17

7-31

8-14

2003 Report week ending 2004

Number of regions

Localized activity Widespread activity

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100

200

300

400

500

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700

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900

1000

35 41 47 53 6 12 18 43 49 3 9 15 21 37 43 49 3 9 15 21 27 35 41 47 1 7 13 19 25 39 45 51 5 11 17 23 29 35 36 42 48 2 8 14 20 26 32 39 45 51 5 11 17 23 29 35

Nu

mb

er

of

Ca

se

s /

No

mb

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e c

as

Influenza A

Influenza B

Week Influenza Season 1997/98 1998/99 1999-2000 2000/01 2001/02 2002/03 2003/04

Predominant strain(s)/ viruses similar to/ viruses similar to/ viruses similar to/ viruses similar to/ viruses similar to/ viruses similar to/ viruses similar to/

Souche(s) Analogues à : Analogues à : Analogues à : Analogues à : Analogues à : Analogues à : Analogues à :prédominante(s) A/Sydney/5/97(H3N2) A/Sydney/5/97(H3N2) A/Sydney/5/97(H3N2) A/NewCaledonia/20/99- A/Panama/2007/99 (H3N2) A/(H1N2) A/Fujian/411/02 (H3N2) B/Beijing/184/93 B/Beijing/184/93 (H1N1) A/H1N2 B/Hong Kong/330/01

Seasonal Distributuion of Laboratory Confirmed Influenza Infections by influenza type, Canada 1997-2004

Influenza Tests, % positive, & ILI rates, Canada, by report week, 2003-2004

0

500

1000

1500

2000

2500

3000

3500

4000

4500

8-30

9-13

9-27

10-1

1

10-2

5

11-8

11-2

2

12-6

12-2

0

1-3

1-17

1-31

2-14

2-28

3-13

3-27

4-10

4-24 5-

8

5-22 6-

5

6-19 7-

3

7-17

7-31

8-14

2003 Report week ending 2004

Number of tests

0

10

20

30

40

50

60

70

80

% Positive

Number of tests % Positive ILI Rate

Proportion of lab-confirmed influenza by age-group, Canada, 2003-2004

Age unknown1%

<5 years33%

5-9 years5%

10-14 years5%

15-24 years11%

25-44 years11%

45-64 years9%

65 years25%

Influenza Strain Identification

B/ Sichuan/ 379/ 99-like [33]

H1N2[1]

A/ Panama/ 2007/ 99 (H3N2)-like

[25]

A/ Fujian/ 411/ 02-like (H3N2) [776]

A/ New Caledonia/ 20/ 99-

like (H1N1) [3]

B/ Hong Kong/ 330/ 01-like

[7]

Influenza Activity Level by Provincial and Territorial Influenza Surveillance Regions, Canada,

Week 03 2004

FluWatch on the Webhttp://www.phac-aspc.gc.ca/fluwatch/index.html

New Initiatives….• Impact of influenza in children -

hospitalizations • Sentinel hospital-based surveillance• Trained nurse monitor at each centre

identifies eligible cases and completes detailed case report forms Admissions by Age-group

2004-05

29%

30%

19%

14%

8%

0-5 months

6-23 months

2-4 years

5-9 years

10-16 years

New Initiatives..

Canadian Network for Public Health Intelligence (CNPHI)

• CNPHI is a secure internet-based suite of applications and resources.

• It is primarily directed towards strategic public health information and intelligence sharing.

• Included applications: – Atlantic Canada FluWatch Application – Canadian Integrated Outbreak Surveillance Centre

(CIOSC).

New Initiatives: CNPHI

Canadian Integrated Outbreak Surveillance Centre (CIOSC)

Canadian Integrated Outbreak Surveillance Centre (CIOSC)

• Goal: To enhance public health’s capacity to anticipate and detect health risks associated with communicable disease threats.

SRI Alerts: An SRI alert is an operational definition used to ensure that individuals meeting specific criteria are identified in a systematic way to allow for implementation of appropriate infection control and public health measures until SARS or other emerging respiratory pathogen has been ruled out as a cause of the illness

Severe Respiratory Illness (SRI) Surveillance

SRI Alerts

An SRI alert is sent under the following situations:

• An individual is hospitalized with an SRI and has a potential epidemiologic link to a source of emerging respiratory pathogen

• Clusters of SRI are identified within a health care unit

• An individual has been identified with laboratory evidence of a SARS-CoV infection (or other emerging respiratory infection)

• An individual has been identified with a laboratory confirmed influenza A/ H5N1 or other novel influenza virus infection