Alberta Respiratory Virus Surveillance Update

Alberta Respiratory Virus Surveillance Report

Update for Flu week 2 (Jan 11 - 17, 2015)

Weekly Update

January 22, 2015

The purpose of this report is to inform Public Health staff, primary care providers, acute care staff and other community

practitioners about recent and historical respiratory virus activity in the province of Alberta. Unless otherwise noted, all data

presented are current up to the Saturday prior to the day the report is released.

Please note: Due to reduced staffing over the holidays CDRS data entry has fallen behind. Numbers presented for outbreaks are likely

an underrepresentation of the true values, due to the data entry delays.

Alberta

RSV had the highest percent positivity among specimens tested for respiratory viruses in week 2, followed by Influenza A (Figure 1).

There were 219 new cases of lab confirmed influenza in week 2 in Alberta; 162 A(H3), 0 A(H1N1)pdm09, 13 A(unresolved subtype), and 44 B

(Table 1). So far this season (August 24, 2014 ¨C January 17, 2015), there have been 3,790 cases of lab confirmed influenza; 3,426 A(H3), 3

A(H1N1)pdm09, 175 A(unresolved subtype) and 186 B.

In week 2, the overall rate for influenza A in Alberta was 4.4 per 100,000 and for influenza B it was 1.1 per 100,000.

In week 2, the 65+ years age group had the highest rate of influenza A(H3) in Alberta.

There were no ILI outbreaks reported with onset in week 2 in Alberta; however this is due to delays of data entry into CDRS rather than no

outbreaks occurring. (Table 2).

The Health Link Alberta call rate for cough/ILI was 17 calls per 100,000 Albertans in week 2 (Figure 6).

There were 505 visits with ILI (5.0% of all visits) to Edmonton zone Emergency Departments/Urgent Care Centres (EDIS/E-triage sites) (Figure

7) and 714 visits with ILI (8.0% of all visits) to Calgary zone Emergency Departments/Urgent Care Centres (SEC sites) in week 2 (Figure 8).

In week 2, 0.93% and 0.50% of patient visits to Alberta sentinel physicians were attributed to ILI (influenza like illness) and LRTI (lower

respiratory tract infection), respectively (Figure 9).

Public health administered influenza immunization data are available in Table 3, Table 4, Table 5, Table 6 and Table 7.

North America

As per FluWatch (PHAC), influenza activity decreased in week 1 in Canada with influenza A(H3N2) predominating.

As of flu week 1, the National Microbiology Lab (NML) of Canada has antigenically characterized 89 influenza samples ¨C 55 A(H3N2), 2

A(H1N1)pdm09, and 32 B. The majority of circulating influenza B (29 of 32) and A(H1N1) (2 of 2) viruses have been antigenically similar (good

match) to the recommended strains for the 2014-15 seasonal influenza vaccine, while the majority of A(H3N2) viruses have shown evidence of

an antigenic drift (sub-optimal match) from the vaccine strain. Of the A(H3N2) viruses 55 were tested by hemagglutination inhibition (HI)

assay; 1 was antigenically similar and 5 showed reduced titers A/Texas/50/2012, and 49 were antigenically similar to

A/Switzerland/9715293/2013. Additionally, sequencing analysis showed that 249 of the 250 A(H3N2) viruses, unable to be tested by HI assay,

belonged to a group that typically shows reduced titers to A/Texas/50/2012.

Quick Links

There were 235 viruses tested for antiviral resistance to oseltamivir and zanamivir and all were sensitive.

Laboratory Data

There were 340 influenza A(H3N2) virus samples tested for resistance to amantadine; all but one (99.7%),

ILI Outbreaks

were resistant.

Calls to Health Link Alberta

According to the week 1 FluView (US CDC) update, influenza activity in the US remained at elevated

Emergency Department Visits

levels. Two hundred and twenty seven (65.0%) of the 349 A(H3N2) viruses tested showed either reduced

TARRANT Sentinel Physician

titers with antiserum produced against A/Texas/50/2012 or belonged to a genetic group that typically

Visits

shows reduced titers to A/Texas/50/2012.

Immunization Data

International

Data Notes

As per the most recent WHO influenza update (January 12, 2015), influenza activity continued to increase

2013-14 Northern

in most areas of the northern hemisphere with influenza A(N3N2) viruses predominating. The antigenic

Hemisphere Vaccine

characterization of most recent A(H3N2) viruses so far indicated differences from the A(H3N2) virus used

Recommendations

in the influenza vaccines for the northern hemisphere 2014-2015. The tested influenza A(H3N2) viruses

Current Global Information

did show sensitivity to neuraminidase inhibitors.

FluWatch (PHAC)

Among the tropical countries, influenza activity remained low, with increases being observed in some

FluView (US CDC)

countries in the Caribbean and tropical Asia.

HPA (UK)

In the southern hemisphere, influenza activity remained low, with the exception of several Pacific Islands.

WHO

Travel Advisories

1

Surveillance and Reporting

Public Health Surveillance and Infrastructure

If you have questions about the Alberta Respiratory Virus Surveillance Report, or any of the indicators, please contact:

AHS.PublicHealthSurveillance@albertahealthservices.ca

Alberta Respiratory Virus Surveillance Report

Update for Flu week 2 (Jan 11 - 17, 2015)

Laboratory Data

Figure 1: Alberta weekly respiratory specimen percent positivity, by virus type

ALBERTA

60%

Percent Positive

50%

40%

30%

20%

10%

0%

35

38

41

44

47

50

53

3

6

9

12

15

18

21

24

27

30

33

Flu Week

Adenovirus

Parainfluenza

Mixed

Coronavirus

RSV

FluA

Hmpv

Rhino-enterovirus

FluB

Click here for ZONE figures of respiratory virus specimen percent positivity

Source: DIAL ¨C Provincial Laboratory specimens, data extracted on January 20, 2015. For more information on data definitions and sources, see Data Notes.

¡°Percent positive¡± is the number of positive specimens for that virus as a percent of the total number of specimens tested for respiratory viruses.

Table 1: New and cumulative laboratory confirmed influenza cases, by subtype, Alberta and Zones

Week 2 (11Jan2015 - 17JAN2015)

Cumulative (24Aug2014 - 17JAN2015)

Influenza A

Influenza B Influenza A

Influenza B

A

A

(unresolved

(unresolved

type due to

type due to

A(H1N1) low viral

A(H1N1) low viral

Zones

A(H3)

pdm09

load)

A (total) B (total)

A(H3)

pdm09

load)

A (total) B (total)

South

26

0

2

28

0

277

0

14

291

2

Calgary

66

0

5

71

18

1097

1

52

1150

72

Central

23

0

1

24

12

440

0

21

461

39

Edmonton

34

0

3

37

7

1108

1

63

1172

51

North

13

0

2

15

7

504

1

25

530

22

Alberta Total

162

0

13

175

44

3426

3

175

3604

186

Source: CDRS influenza cases, data extracted on January 21, 2015. For more information on data definitions and sources, see Data Notes.

2

Surveillance and Reporting

Public Health Surveillance and Infrastructure

If you have questions about the Alberta Respiratory Virus Surveillance Report, or any of the indicators, please contact:

AHS.PublicHealthSurveillance@albertahealthservices.ca

Alberta Respiratory Virus Surveillance Report

Update for Flu week 2 (Jan 11 - 17, 2015)

Figure 2: Alberta weekly rates (per 100,000) of lab confirmed influenza, by subtype

ALBERTA

Weekly rate (per 100,000)

25

20

15

10

5

0

35

38

41

44

47

50

53

3

Influenza A rate (2014-15)

6

9

12

15

Flu week

Influenza A rate (2013-14)

Influenza B rate (2014-15)

Influenza B rate (2013-14)

18

21

24

27

30

33

Influenza A rate (2012-13)

Influenza B rate (2012-13)

Click here for ZONE figures - rates of lab confirmed influenza

Source: CDRS influenza cases, data extracted on January 21, 2015. For more information on data definitions and sources, see Data Notes.

Figure 3: Alberta weekly rates (per 100,000) of lab confirmed respiratory viruses (excluding influenza), by virus type

ALBERTA

Weekly Rate (per 100,000)

10

8

6

4

2

0

35

38

41

Adenovirus rate

RSV rate

44

47

50

53

3

Coronavirus rate

Mixed rate

6

Flu Week

9

12

15

18

hMPV rate

Rhino-enterovirus rate

21

24

27

30

33

Parainfluenza rate

Click here for ZONE figures - rates of lab confirmed respiratory viruses

Source: DIAL ¨C Provincial Laboratory specimens, data extracted on January 20, 2015. For more information on data definitions and sources, see Data Notes.

3

Surveillance and Reporting

Public Health Surveillance and Infrastructure

If you have questions about the Alberta Respiratory Virus Surveillance Report, or any of the indicators, please contact:

AHS.PublicHealthSurveillance@albertahealthservices.ca

Alberta Respiratory Virus Surveillance Report

Update for Flu week 2 (Jan 11 - 17, 2015)

Figure 4: Alberta weekly age-specific rates of lab confirmed influenza (per 100,000) by subtype

Age Specific Rate (per 100,000)

ALBERTA Influenza A(H1N1)PDM09

0 to < 2 years

80

70

60

50

40

30

20

10

0

2 to < 5 years

5 to < 9 years

9 to < 18 years

18 to < 65 years

65+ years

35

38

41

44

47

50

53

3

6

9

12

15

18

21

24

27

30

33

Age Specific Rate (per 100,000)

Flu Week

ALBERTA Influenza A(H3)

80

70

60

50

40

30

20

10

0

0 to < 2 years

2 to < 5 years

5 to < 9 years

9 to < 18 years

18 to < 65 years

65+ years

35

38

41

44

47

50

53

3

6

9

12

15

18

21

24

27

30

33

Age Specific Rate (per 100,000)

Flu Week

ALBERTA Influenza B

80

70

60

50

40

30

20

10

0

0 to < 2 years

2 to < 5 years

5 to < 9 years

9 to < 18 years

18 to < 65 years

65+ years

35

38

41

44

47

50

53

3

6

9

12

15

18

21

24

27

30

33

Flu Week

Click here for ZONE figures - age specific rates of lab confirmed influenza

Source: CDRS influenza cases, data extracted on January 21, 2015. For more information on data definitions and sources, see Data Notes.

4

Surveillance and Reporting

Public Health Surveillance and Infrastructure

If you have questions about the Alberta Respiratory Virus Surveillance Report, or any of the indicators, please contact:

AHS.PublicHealthSurveillance@albertahealthservices.ca

Alberta Respiratory Virus Surveillance Report

Update for Flu week 2 (Jan 11 - 17, 2015)

Please note: Due to reduced staffing over the holidays CDRS data entry has fallen behind. Numbers presented for outbreaks are likely

an underrepresentation of the true values, due to the data entry delays.

Influenza-Like-Illness (ILI) Outbreak Investigations

Number of Outbreaks

Figure 5: AHS investigated ILI outbreaks in Alberta facilities, by onset week and organism type

40

30

All AHS reported

Influenza-Like-Illness

Outbreaks*

20

10

0

Number of Outbreaks

35

Number of Outbreaks

41

44

47

50

1

4

7

10

13

16

19

22

25

28

31

34

40

30

Confirmed

Influenza A(H3)

20

10

0

35

38

41

44

47

50

1

4

7

10

13

16

19

22

25

28

31

34

20

15

Confirmed

Influenza A(H1N1)

10

5

0

35

Number of Outbreaks

38

38

41

44

47

50

1

4

7

10

13

16

19

22

25

28

31

34

20

15

Confirmed

Influenza B

10

5

0

35

38

Acute Care

41

44

Childcare

47

50

1

4

Long term Care

7

10 13

Flu Week

16

School (K-12)

- - - Combined total for the 2013-14 season

19

22

25

28

31

34

Supportive or Home Living Sites (SL/HL)

Other

¨D Combined total for the 2012-13 season

Source: CDRS data extracted on January 21, 2015 (obtained via the Alberta Outbreak Reporting Form). For more information on data definitions and sources, see Data

Notes.

Note: Some outbreaks may involve more than one pathogen.

5

Surveillance and Reporting

Public Health Surveillance and Infrastructure

If you have questions about the Alberta Respiratory Virus Surveillance Report, or any of the indicators, please contact:

AHS.PublicHealthSurveillance@albertahealthservices.ca

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