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Influenza Surveillance
at IRID
Immunization and Respiratory Infections Division
Centre for Infectious Disease Prevention & Control
Public Health Agency of Canada
Impact of Influenza
In 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
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 subtypes
4) Contribute to the information for vaccine composition for following
season
Influenza Surveillance
Data Provider
Sentinel Physicians
Laboratories
National
Microbiology
Laboratory
Provincial/Territorial
Epidemiologists
Indicator
ILI Consultations
Number of Influenza
tests and positives
Strain
Characterization
Influenza activity
levels (outbreaks
etc)
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
Number of regions
30
25
20
15
10
5
2003
Report week ending
Localized activity
2004
Widespread activity
8-14
7-31
7-17
7-3
6-19
6-5
5-22
5-8
4-24
4-10
3-27
3-13
2-28
2-14
1-31
1-17
1-3
12-20
12-6
11-22
11-8
10-25
10-11
9-27
9-13
8-30
0
Seasonal Distributuion of Laboratory Confirmed Influenza Infections
by influenza type, Canada 1997-2004
1000
Influenza A
Influenza B
900
Number of Cases / Nombre de cas
800
700
600
500
400
300
200
100
0
Week
Influenza Season
35 41 47 53 6 12 18
1997/98
Predominant strain(s)/
Souche(s)
prédominante(s)
43 49 3 9 15 21 37 43 49 3 9 15 21 27 35 41 47 1 7 13 19 25
1998/99
1999-2000
2000/01
39 45 51 5 11 17 23 29 35 36 42 48 2 8 14 20 26 32
2001/02
viruses similar to/ viruses similar to/ viruses similar to/
viruses similar to/
viruses similar to/
Analogues à :
Analogues à :
Analogues à :
Analogues à :
Analogues à :
A/Sydney/5/97(H3N2) A/Sydney/5/97(H3N2) A/Sydney/5/97(H3N2) A/NewCaledonia/20/99- A/Panama/2007/99 (H3N2)
B/Beijing/184/93
B/Beijing/184/93
(H1N1)
A/H1N2
2002/03
viruses similar to/
Analogues à :
A/(H1N2)
B/Hong Kong/330/01
39 45 51 5 11 17 23 29 35
2003/04
viruses similar to/
Analogues à :
A/Fujian/411/02 (H3N2)
Influenza Tests, % positive, & ILI rates, Canada, by
report week, 2003-2004
Number of tests
% Positive
4500
80
4000
70
3500
60
3000
50
2500
40
2000
30
1500
1000
20
500
10
2003
Report w eek ending
Number of tests
% Positive
2004
ILI Rate
8-14
7-31
7-17
7-3
6-19
6-5
5-22
5-8
4-24
4-10
3-27
3-13
2-28
2-14
1-31
1-17
1-3
12-20
12-6
11-22
11-8
10-25
10-11
9-27
9-13
0
8-30
0
Proportion of lab-confirmed influenza by agegroup, Canada, 2003-2004
Age unknown
1%
65 years
25%
<5 years
33%
45-64 years
9%
5-9 years
5%
25-44 years
11%
15-24 years
11%
10-14 years
5%
Influenza Strain Identification
H1N2
[1]
B/Hong
Kong/330/01-like
[7]
B/Sichuan/379/99like [33]
A/Panama/2007/99
(H3N2)-like
[25]
A/Fujian/411/02like (H3N2) [776]
A/New
Caledonia/20/99like (H1N1)
[3]
Influenza Activity Level by Provincial and Territorial Influenza
Surveillance Regions, Canada,
Week 03 2004
FluWatch on the Web
http://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
Admissions by Age-group
detailed case report forms
2004-05
8%
14%
29%
0-5 months
6-23 months
2-4 years
19%
5-9 years
30%
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.
Severe Respiratory Illness (SRI) Surveillance
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
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