Provincial Respiratory Surveillance Report

Seasonal Influenza


Seasonal influenza can result in severe morbidity and mortality. Year-round monitoring of influenza across Manitoba is performed by Epidemiology and Surveillance (E&S) in collaboration with Cadham Provincial Laboratory (CPL) through a variety of indicators. This report provides a weekly update on the provincial influenza activity during a season.

Data are reported with a one-week delay for increased data accuracy, completeness and reliability. More analyses may be conducted and will be added to this report when available. It is published online at approximately 3:00pm every Friday.

Week 20 (May 15 – May 21)

About epidemiological week

Data extracted up to 1:00 am on May 26, 2022
Next reporting date: June 3, 2022

Influenza: Decreased Activity

In Manitoba, the number of influenza cases increased in the last six weeks, higher than we would normally see for this time of year, and peaked in Week 17. In Week 20, there were 6 new laboratory-confirmed influenza A cases reported. Activity level in other respiratory indicators continued to be lower than or within the expected levels for this time of year.


Since the beginning of April, detections of influenza have sharply increased. Influenza activity has reached seasonal thresholds.

Cases

About cases

New cases this week

  • Influenza A: 6
  • Influenza B: 0

Total

  • Influenza A: 293
  • Influenza B: 0

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Severity

About severity

Severe outcomes associated with influenza

This week

  • Hospitalizations: 1
  • ICU admissions: 0
  • Deaths: 0

Total

  • Hospitalizations: 54
  • ICU admissions: 2
  • Deaths: 2

Outbreaks

About outbreaks

Labratory-confirmed influenza outbreaks

This week

  • Influenza A: 0
  • Influenza B: 0
  • Influenza A & B: 0

Total

  • Influenza A: 3
  • Influenza B: 0
  • Influenza A & B: 0

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Vaccination

About Vaccination

Residents immunized: 400,121 (28.6%)

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Syndromic Indicators: Low Activity

The respiratory activity levels in the community, primary care and emergency rooms continued to be low for this time of a year.

FluWatchers

About FluWatchers

Participants reporting: 560

Reporting fever and cough: 2.1%

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Physician Visits

About sentinal physicians

Influenza Like Illness (ILI) Visits to sentinel physicians: 2.4%

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Antiviral

About Antiviral

Units of antiviral dispensed from pharmacies: 7


Influenza isolates resistant to antiviral this season in Canada

  • Oseltamivir: 0
  • Zanamivir: 0

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ED Visits

About emergency room visits

Average daily respiratory visits to emergency department (ED): 130

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Important Notes

  1. Data about influenza cases are extracted from PHIMS.
  2. Numbers are subject to change. Missed events in the current report due to reporting delays will be included in later reports when data becomes available.

Cases

Figure 1. Weekly Cases of Laboratory-Confirmed Influenza, Manitoba, 2018 – May 21, 2022

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Figure 2. Age Distribution of Laboratory-Confirmed Influenza Cases, Manitoba, September 1, 2021 – May 21, 2022

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Table 1. Cases of Influenza by Health Region, Manitoba, September 1, 2021 – May 21, 2022

Health Region Total Influenza A Total Influenza B Influenza A this week Influenza B this week
Winnipeg RHA 65 0 1 0
Southern Health-Santé Sud 12 0 0 0
Interlake-Eastern RHA 26 0 1 0
Prairie Mountain Health 12 0 0 0
Northern Health Region 178 0 4 0
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Table 2. Antiviral Resistance of Isolates by Influenza Type and Subtype, Manitoba, September 1, 2021 – May 19, 2022

Oseltamivir
Zanamivir
Resistant Susceptible Resistant Susceptible
Canada
A (H3N2) 0 94 0 94
A (H1N1) 0 4 0 4
B 0 0 0 0
Manitoba
A (H3N2) 0 55 0 55
A (H1N1) 0 1 0 1
B 0 0 0 0
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Table 3. Influenza Strain Characterization reported by National Microbiology Laboratory, Manitoba, September 1, 2021 – May 19, 2022

Strain
Number of viruses
Canada Manitoba
A/Cambodia/e0826360/2020 (H3N2)-like 91 55
A/Wisconsin/588/2019 (H1N1)-like 4 1
B/Washington/02/2019-like 0 0
B/Phuket/3073/2013-like 0 0

Note: As per the World Health Organization (WHO), all seasonal quadrivalent influenza vaccines for 2021-2022 in the northern hemisphere contain those strains.

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Outbreaks

Figure 3. Weekly Respiratory and Influenza Outbreaks, Manitoba, 2018 – May 21, 2022

Note: COVID-19 outbreaks were not included.

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Vaccinations

Table 4. Age Distribution and Coverage of Vaccinations, Manitoba, September 1, 2021 – May 21, 2022

Age Group Doses Coverage Percentage
0-4 23,797 22.6%
5-14 31,673 17.7%
15-49 115,689 17.9%
50-64 88,990 34.0%
65+ 146,133 62.5%
All 406,282 28.6%

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FluWatchers

Figure 4. Weekly FluWatchers Participants and Percentage Reporting Fever and Cough, Manitoba, 2018 – May 21, 2022

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Physician Visits

Figure 5. Weekly Percentage of ILI Related Visits to Sentinel Physicians, Manitoba, 2018 – May 21, 2022

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Antiviral

Figure 6. Weekly Units of Antiviral Dispensed from Pharmacies, Manitoba, 2018 – May 21, 2022

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ED Visits

Figure 7. Weekly Respiratory Visits to Emergency Department, Winnipeg Regional Health Authority, Manitoba, 2018 – May 21, 2022

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Epidemiology and Surveillance

epiCOVID@gov.mb.ca

Other Epidemiology and Surveillance reports

https://www.gov.mb.ca/health/publichealth/surveillance/index.html