FluWatch report: November 23 to November 29, 2014 (Week 48)
Overall summary
- In week 48, laboratory detections of influenza increased sharply for the second consecutive week (twice the number detected in week 47) and hospitalizations with influenza also increased. The majority of laboratory detections and hospitalizations continued to be reported in BC, AB, ON and QC; but with increasing activity in SK and MB.
- A(H3N2) continues to be the most common type of influenza affecting Canadians. In both laboratory detections and hospitalizations, the majority of cases have been among seniors ≥65 years of age.
- Similar to the previous week, there was a large number of newly-reported laboratory-confirmed outbreaks of influenza in week 48: 21 reported in 5 provinces, of which 17 were in long-term care facilities.
Are you a primary health care practitioner (General Practitioner, Nurse Practitioner or Registered Nurse) interested in becoming a FluWatch sentinel for the 2014-15 influenza season? Contact us at FluWatch@phac-aspc.gc.ca
On this page
- Influenza/ILI Activity (geographic spread)
- Influenza and Other Respiratory Virus Detections
- Antiviral Resistance
- Influenza Strain Characterizations
- Influenza-like Illness (ILI) Consultation Rate
- Influenza Outbreak Surveillance
- Pharmacy surveillance
- Sentinel Hospital Influenza Surveillance
- Provincial/Territorial Influenza Hospitalizations and Deaths
- Emerging Respiratory Pathogens
- International Influenza Reports
Download the alternative format
(PDF format, 307 KB, 10 pages)
Related Topics
Influenza/ILI Activity (geographic spread)
In week 47, eleven regions (in BC(2), AB(2), SK(1), ON(3), QC(2), and PE(1)) reported localized activity and 15 regions (BC(2), AB(3), SK(1), MB(1), ON(1), QC(4), NS(1), NL(1) and YT(1)) reported sporadic activity (Figure 1).
Influenza and Other Respiratory Virus Detections
In week 48, the number of positive influenza tests increased sharply for the second week in a row, to 630 influenza detections (15.2% of tests), predominantly due to influenza A (Figure 2). To date, 94% of influenza detections have been influenza A, and 99% of those subtyped have been A(H3) (Table 1). The timing of the season and predominant A(H3N2) subtype is similar to the pattern observed during the 2012-13 influenza season. To date, among the cases of influenza A with reported age, the largest proportion was in adults ≥65 years of age (61%) (Table 2).
In week 48, detections of RSV continued to follow an upward trend, in keeping with its usual pattern of seasonal circulation. Detections of parainfluenza and adenovirus also continue to follow their seasonal patterns of broad winter circulation. Detections of rhinovirus peaked in week 39 and continue to follow a downward trend (figure 3).
For more details, see the weekly Respiratory Virus Detections in Canada Report.
Reporting provincesFootnote 1 | Weekly (November 23 to November 29, 2014) | Cumulative (August 24 to November 29, 2014) | ||||||||
---|---|---|---|---|---|---|---|---|---|---|
Influenza A | B | Influenza A | B | |||||||
A Total | A(H1)pdm09 | A(H3) | A Footnote (Uns) | B Total | A Total | A(H1)pdm09 | A(H3) | A(UnS) | B Total | |
BC | 32 | 0 | 22 | 10 | 0 | 131 | 2 | 118 | 11 | 9 |
AB | 228 | 0 | 195 | 33 | 7 | 589 | 0 | 545 | 44 | 30 |
SK | 14 | 0 | 9 | 5 | 1 | 25 | 0 | 14 | 11 | 1 |
MB | 6 | 0 | 1 | 5 | 0 | 12 | 0 | 7 | 5 | 1 |
ON | 82 | 0 | 57 | 25 | 1 | 206 | 4 | 147 | 55 | 16 |
QC | 244 | 0 | 0 | 244 | 12 | 396 | 0 | 0 | 396 | 30 |
NB | 1 | 0 | 1 | 0 | 0 | 3 | 0 | 1 | 2 | 0 |
NS | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 2 |
PE | 2 | 0 | 2 | 0 | 0 | 4 | 0 | 3 | 1 | 1 |
NL | 0 | 0 | 0 | 0 | 0 | 2 | 0 | 1 | 1 | 0 |
Canada | 609 | 0 | 287 | 322 | 21 | 1369 | 6 | 837 | 526 | 90 |
Percentage Footnote 2 | 96.7% | 0.0% | 47.1% | 52.9% | 3.3% | 93.8% | 0.4% | 61.1% | 38.4% | 6.2% |
Age groups (years) | Weekly (November 23 to November 29, 2014) |
Cumulative (August 24 to November 29, 2014) |
||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Influenza A | B | Influenza A | B | Influenza A and B | ||||||||
A Total | A(H1) pdm09 | A(H3) | A Footnote (Uns) | Total | A Total | A(H1) pdm09 | A(H3) | A (UnS) | Total | # | % | |
<5 | 48 | 0 | 34 | 14 | 2 | 29 | 2 | 14 | 13 | 7 | 36 | 3.5% |
5-19 | 52 | 0 | 35 | 17 | 4 | 71 | 2 | 36 | 33 | 9 | 80 | 7.8% |
20-44 | 67 | 0 | 36 | 31 | 7 | 87 | 0 | 44 | 43 | 20 | 107 | 10.4% |
45-64 | 72 | 0 | 27 | 45 | 7 | 159 | 0 | 105 | 54 | 13 | 172 | 16.8% |
65+ | 282 | 0 | 83 | 199 | 12 | 604 | 1 | 357 | 246 | 25 | 629 | 61.4% |
Unknown | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 1 | 0.1% |
Total | 521 | 0 | 215 | 306 | 32 | 951 | 5 | 556 | 390 | 74 | 1025 | 100.0% |
PercentageFootnote 2 | 94.2% | 0.0% | 41.3% | 58.7% | 5.8% | 92.8% | 0.5% | 58.5% | 41.0% | 7.2% | ||
Influenza Strain Characterizations
During the 2014-2015 influenza season, the National Microbiology Laboratory (NML) has characterized 23 influenza viruses [10 A(H3N2) and 13 influenza B]. Two influenza A viruses were antigenically similar to A/Texas/50/2012, and 10 influenza B viruses were antigenically similar to the B/Massachusetts/2/2012 (Yamagata lineage) recommended by the WHO for the 2014-15 seasonal influenza vaccine. Eight influenza A(H3N2) viruses and three influenza B viruses showed reduced titers to antisera produced against strains recommended for the seasonal influenza vaccine (Figure 4).
Figure 4. Influenza strain characterizations, Canada, 2014-2015, N = 23
The NML receives a proportion of the number of influenza positive specimens from provincial laboratories for strain characterization and antiviral resistance testing. Characterization data reflect the results of haemagglutination inhibition (HAI) testing compared to the reference influenza strains recommended by WHO.
The recommended components for the 2014-2015 northern hemisphere trivalent influenza vaccine include: an A/California/7/2009(H1N1)pdm09-like virus, an A/Texas/50/2012 (H3N2)-like virus, and a B/Massachusetts/2/2012-like virus (Yamagata lineage). For quadrivalent vaccines, the addition of a B/Brisbane/60/2008-like virus is recommended.
Figure 4 - Text Description
Strain | Number of specimens | Percentage |
---|---|---|
A/Texas/50/2012-like | 2 | 9% |
reduced titres to A/Texas/50/2012 | 8 | 35% |
A/California/07/2009-like | 0 | 0% |
reduced titres to A/California/07/2009 | 0 | 0% |
B/Massachusetts/2/2012-like | 10 | 43% |
reduced titres to B/Massachusetts/2/2012 | 3 | 13% |
B/Brisbane/60/2008-like | 0 | 0% |
Antiviral Resistance
During the 2014-2015 influenza season, NML has tested 49 influenza viruses for resistance to oseltamivir and zanamivir and all were sensitive to both agents. The 57 influenza A(H3N2) viruses tested for amantadine resistance were all resistant (Table 3).
Virus type and subtype | Oseltamivir | Zanamivir | Amantadine | |||
---|---|---|---|---|---|---|
# tested | # resistant (%) | # tested | # resistant (%) | # tested | # resistant (%) | |
A (H3N2) | 36 | 0 | 36 | 0 | 57 | 57 (100%) |
A (H1N1) | 0 | 0 | 0 | 0 | 0 | 0 |
B | 13 | 0 | 13 | 0 | NATable 3 - Footnote * | NA Table 3 - Footnote * |
TOTAL | 49 | 0 | 49 | 0 | 57 | 46 |
Influenza-like Illness (ILI) Consultation Rate
The national influenza-like-illness (ILI) consultation rate increased in week 48 to 29.1 consultations per 1,000, which is above expected levels for week 48 (Figure 5). To date this season, the rates have been highest among those <20 years of age.
Influenza Outbreak Surveillance
In week 48, 21 new outbreaks of influenza A were reported: 17 in long-term care facilities (LTCF), three in hospitals and one in another institutional or community setting (Figure 6). Among the five LTCF outbreaks in which the influenza subtype was known, all were A(H3N2); the outbreak in another setting was associated with A(H1N1)pdm09. To date this season, 52 outbreaks in LTCF have been reported.
Figure 6: Overall number of new laboratory-confirmed influenza outbreaks by report week, Canada, 2014-2015
1 All provinces and territories except NU report outbreaks in long-term care facilities. All provinces and territories with the exception of NU and QC report outbreaks in hospitals. Outbreaks of influenza or influenza-like-illness in other facilities are reported to FluWatch but reporting varies between jurisdictions. Outbreak definitions are included at the end of the report.
Figure 6 - Text Description
Report week | Hospitals | Long Term Care Facilities | Other |
---|---|---|---|
35 | 0 | 0 | 0 |
36 | 0 | 0 | 0 |
37 | 0 | 0 | 0 |
38 | 0 | 1 | 0 |
39 | 0 | 5 | 5 |
40 | 0 | 0 | 0 |
41 | 0 | 2 | 0 |
42 | 0 | 3 | 0 |
43 | 0 | 2 | 0 |
44 | 0 | 1 | 0 |
45 | 0 | 2 | 0 |
46 | 0 | 3 | 0 |
47 | 0 | 16 | 1 |
48 | 0 | 17 | 1 |
Pharmacy surveillance
During week 48, the proportion of prescriptions for antivirals increased to 35.5 antiviral prescriptions per 100,000 total prescriptions, which is in keeping with previous seasons (Figure 7).
Sentinel Hospital Influenza Surveillance
Paediatric Influenza Hospitalizations and Deaths (IMPACT)
In week 48, 13 laboratory-confirmed influenza-associated paediatric (≤16 years of age) hospitalizations were reported by the Immunization Monitoring Program Active (IMPACT) network: 12 cases of influenza A and one case of influenza B (Figure 8a). To date this season, 51 hospitalizations have been reported by the IMPACT network, 46 (90%) of which were cases of influenza A. Among cases for which the influenza A subtype was reported, 35/37 were A(H3N2). The majority of cases (67%) were in children <5 years of age (Table 4). To date, six cases were admitted to the ICU (Figure 9a).
Note: The number of hospitalizations reported through IMPACT represents a subset of all influenza-associated paediatric hospitalizations in Canada. Delays in the reporting of data may cause data to change retrospectively.
Adult Influenza Hospitalizations and Deaths (PCIRN)
In week 48, 26 laboratory-confirmed influenza-associated adult (≥16 years of age) hospitalizations were reported by the PHAC/CIHR Influenza Research Network (PCIRN) Serious Outcomes Surveillance (SOS) network: 25 cases of influenza A and one case of influenza B (Figure 8b). To date this season, 36 cases have been reported; 35 (97%) with influenza A. The majority of cases (83%) were among adults ≥65 years of age (Table 5). Two ICU admissions and one death have been reported, all adults ≥65 years of age with underlying conditions or comorbidities (Figure 8b).
Note: The number of hospitalizations reported through CIRN represents a subset of all influenza-associated adult hospitalizations in Canada. Delays in the reporting of data may cause data to change retrospectively.
Age groups | Cumulative (Aug. 24, 2014 to November 29, 2014) | |||||
---|---|---|---|---|---|---|
Influenza A | B | Influenza A and B | ||||
A Total | A(H1) pdm09 | A(H3) | AFootnote (Uns) | Total | # (%) | |
0-5m | 6 | 0 | 6 | 0 | 0 | 6(11.8%) |
6-23m | 8 | 1 | 7 | 0 | 0 | 8 (15.7%) |
2-4y | 17 | 1 | 13 | 3 | 1 | 18 (35.3%) |
5-9y | 7 | 0 | 4 | 3 | 3 | 10 (19.6%) |
10-16y | 8 | 0 | 5 | 3 | 1 | 9 (17.6%) |
Total | 46 | 2 | 35 | 9 | 5 | 51 |
% Footnote 1 | 90.2% | 4.3% | 76.1% | 19.6% | 9.8% | 100.0% |
Age groups | Cumulative (November 23, 2014 to Niovember 29, 2015) | |||||
---|---|---|---|---|---|---|
Influenza A | B | Influenza A and B | ||||
A Total | A(H1) pdm09 | A(H3) | AFootnote (Uns) | Total | # (%) | |
16-20 | 2 | 0 | 0 | 2 | 0 | 2 (6%) |
20-44 | 1 | 0 | 0 | 1 | 1 | 2 (6%) |
45-64 | 2 | 0 | 1 | 1 | 0 | 2 (6%) |
65+ | 30 | 0 | 2 | 28 | 0 | 30 (83%) |
Total | 35 | 0 | 3 | 32 | 1 | 36 |
% Footnote 1 | 97% | 0% | 9% | 91% | 3% | 100% |
Figure 8 - Number of cases of influenza reported by sentinel hospital networks, by week, Canada, 2014-15
A) Paediatric hospitalizations (≤16 years of age, IMPACT)
Figure 8A - Text Description
Report week | Influenza A | Influenza B |
---|---|---|
35 | 0 | 0 |
36 | 0 | 0 |
37 | 2 | 0 |
38 | 1 | 0 |
39 | 1 | 0 |
40 | 1 | 0 |
41 | 2 | 0 |
42 | 1 | 0 |
43 | 2 | 1 |
44 | 4 | 0 |
45 | 4 | 0 |
46 | 8 | 2 |
47 | 8 | 1 |
48 | 12 | 1 |
Figure 8B - Number of cases of influenza reported by sentinel hospital networks, by week, Canada, 2014-15
B) Adult hospitalizations (≥16 year of age, PCIRN-SOS)
Figure 8B - Text Description
Semaine de déclaration | Influenza A | Influenza B | Influenza de type inconnu |
---|---|---|---|
35 | n/a | n/a | n/a |
36 | n/a | n/a | n/a |
37 | n/a | n/a | n/a |
38 | n/a | n/a | n/a |
39 | n/a | n/a | n/a |
40 | n/a | n/a | n/a |
41 | n/a | n/a | n/a |
42 | n/a | n/a | n/a |
43 | n/a | n/a | n/a |
44 | n/a | n/a | n/a |
45 | n/a | n/a | n/a |
46 | 0 | 0 | 0 |
47 | 8 | 0 | 0 |
48 | 25 | 1 | 0 |
Figure 9 - Percentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group, Canada, 2014-15
A) Paediatric hospitalizations (≤16 years of age, IMPACT)
Figure 9A - Text Description
Age-group (years) | Hospitalizations (n=51) | ICU admissions (n=6) |
---|---|---|
0-5m | 11.8% | 0.0% |
6-23m | 15.7% | 16.7% |
2-4y | 35.3% | 33.3% |
5-9y | 19.6% | 0.0% |
10-16y | 17.6% | 50.0% |
Adult hospitalizations (≥16 year of age, PCIRN-SOS)
Figure 9B - Text Description
Age-group (years) | Hospitalizations (n=36) | ICU admissions(n=2) | Deaths (n=1) |
---|---|---|---|
16-20 | 5.6% | 0.0% | 0.0% |
20-44 | 5.6% | 0.0% | 0.0% |
45-64 | 5.6% | 0.0% | 0.0% |
65+ | 83.3% | 100% | 100% |
Provincial/Territorial Influenza Hospitalizations and Deaths
In week 48, 50 laboratory-confirmed influenza-associated hospitalizations were reported from participating provinces and territoriesFootnote *; all but one with influenza A, and 78% were patients ≥65 years of age. Since the start of the 2014-15 season, 224 hospitalizations have been reported; 215 (96%) with influenza A. Among cases for which the subtype of influenza A was reported, 175/177 were A(H3N2). The majority of cases (59%) were ≥65 years of age (Table 6). Three ICU admissions have been reported in adults ≥65 years of age with influenza A. Eighteen deaths with influenza A have been reported: one child <5 years of age, one adult 45-64 years and 16 adults ≥65 years of age. Detailed clinical information (e.g. underlying medical conditions) is not known for these cases.
Age groups | Cumulative (24 August, 2014 to 29 November, 2014) | |||||
---|---|---|---|---|---|---|
Influenza A | B | Influenza A and B | ||||
A Total | A(H1) pdm09 | A(H3) | AFootnote (Uns) | Total | # (%) | |
0-4 years | 21 | 1 | 18 | 2 | 0 | 21 (9%) |
5-19 years | 20 | 0 | 18 | 2 | 1 | 21 (9%) |
20-44 years | 21 | 1 | 18 | 2 | 2 | 23 (10%) |
45-64 years | 22 | 0 | 19 | 3 | 2 | 24 (11%) |
65+ years | 127 | 0 | 98 | 29 | 4 | 131 (58%) |
Unknown | 4 | 0 | 4 | 0 | 0 | 4 (2%) |
Total | 215 | 2 | 175 | 38 | 9 | 224 |
Percentage Footnote 1 | 96.0% | 0.9% | 81.4% | 17.7% | 4.0% | 100.0% |
See additional data on Reported Influenza Hospitalizations and Deaths in Canada: 2009-10 to 2014-15 on the Public Health Agency of Canada website.
Emerging Respiratory Pathogens
Human Avian Influenza
Influenza A(H7N9): Since the last FluWatch report, no new laboratory-confirmed cases of human infection with avian influenza A(H7N9) virus have been reported by the World Health Organization. Globally to December 4, 2014, the WHO has been informed of a total of 458 laboratory-confirmed human cases with avian influenza A(H7N9) virus, including 177 deaths.
Documents related to the public health risk of influenza A(H7N9), as well as guidance for health professionals and advice for the public is updated regularly on the following websites:
PHAC - Avian influenza A(H7N9)
WHO - Avian Influenza A(H7N9)
Middle East Respiratory Syndrome Coronavirus (MERS-CoV)
Since the last FluWatch report, 18 new laboratory-confirmed cases of MERS-CoV, including 4 deaths, have been reported by the World Health Organization. Globally, from September 2012 to December 4, 2014, the WHO has been informed of a total of 927 laboratory-confirmed cases of infection with MERS-CoV, including 338 deaths. All cases have either occurred in the Middle East or have had direct links to a primary case infected in the Middle East. The public health risk posed by MERS-CoV in Canada remains low (see the PHAC Assessment of Public Health Risk).
Documents related to the public health risk of MERS-CoV, as well as guidance for health professionals and advice for the public is updated regularly on the following websites:
Avian Influenza A(H5)
The Canadian Food Inspection Agency (CFIA)'s testing at the National Centre for Foreign Animal Diseases has confirmed the strain causing the avian influenza outbreak on two farms in the Fraser Valley as a highly-pathogenic H5N2 virus. No human cases have been reported. Avian influenza viruses do not pose risks to food safety when poultry and poultry products are properly handled and cooked. Avian influenza rarely affects humans that do not have consistent contact with infected birds. Further information on the outbreak is provided on the following CFIA website:
Enterovirus D68 (EV-D68)
Information related to enterovirus D68, as well as guidance for health professionals and advice for the public is updated regularly:
International Influenza Reports
- World Health Organization influenza update
- World Health Organization FluNet
- WHO Influenza at the human-animal interface
- Centers for Disease Control and Prevention seasonal influenza report
- European Centre for Disease Prevention and Control - epidemiological data
- South Africa Influenza surveillance report
- New Zealand Public Health Surveillance
- Australia Influenza Report
- Pan-American Health Organization Influenza Situation Report
FluWatch definitions for the 2014-2015 season
Abbreviations: Newfoundland/Labrador (NL), Prince Edward Island (PE), New Brunswick (NB), Nova Scotia (NS), Quebec (QC), Ontario (ON), Manitoba (MB), Saskatchewan (SK), Alberta (AB), British Columbia (BC), Yukon (YT), Northwest Territories (NT), Nunavut (NU).
Influenza-like-illness (ILI): Acute onset of respiratory illness with fever and cough and with one or more of the following - sore throat, arthralgia, myalgia, or prostration which is likely due to influenza. In children under 5, gastrointestinal symptoms may also be present. In patients under 5 or 65 and older, fever may not be prominent.
ILI/Influenza outbreaks
- Schools:
-
Greater than 10% absenteeism (or absenteeism that is higher (e.g. >5-10%) than expected level as determined by school or public health authority) which is likely due to ILI.
Note: it is recommended that ILI school outbreaks be laboratory confirmed at the beginning of influenza season as it may be the first indication of community transmission in an area. - Hospitals and residential institutions:
- two or more cases of ILI within a seven-day period, including at least one laboratory confirmed case. Institutional outbreaks should be reported within 24 hours of identification. Residential institutions include but not limited to long-term care facilities ( LTCF) and prisons.
- Workplace:
- Greater than 10% absenteeism on any day which is most likely due to ILI.
- Other settings:
- two or more cases of ILI within a seven-day period, including at least one laboratory confirmed case; i.e. closed communities.
Note that reporting of outbreaks of influenza/ILI from different types of facilities differs between jurisdictions.
Influenza/ILI activity level
1 = No activity: no laboratory-confirmed influenza detections in the reporting week, however, sporadically occurring ILI may be reported
2 = Sporadic: sporadically occurring ILI and lab confirmed influenza detection(s) with no outbreaks detected within the influenza surveillance region Footnote †
3 = Localized:
- evidence of increased ILIFootnote * and
- lab confirmed influenza detection(s) together with
- outbreaks in schools, hospitals, residential institutions and/or other types of facilities occurring in less than 50% of the influenza surveillance regionFootnote †
4 = Widespread:
- evidence of increased ILIFootnote * and
- lab confirmed influenza detection(s) together with
- outbreaks in schools, hospitals, residential institutions and/or other types of facilities occurring in greater than or equal to 50% of the influenza surveillance regionFootnote †
Note: ILI data may be reported through sentinel physicians, emergency room visits or health line telephone calls.
We would like to thank all the Fluwatch surveillance partners who are participating in this year's influenza surveillance program.
Page details
- Date modified: