Provincial Respiratory Surveillance Report

COVID-19 and Seasonal Influenza

2022-2023


This weekly report provides a current epidemiological update on the intensity and severity of respiratory activity in Manitoba including laboratory confirmed activity of both COVID-19 and seasonal influenza. Surveillance data include syndromic indicators, laboratory testing, associated hospitalization and mortality, and outbreaks. Updates around immunization coverage in COVID-19 and seasonal influenza are also included.

Data are reported with a one-week delay for increased data accuracy, completeness and reliability. More analyses continue to be conducted and will be added to this report as available. It is published online at approximately 10:00am every Friday.

Week 49 (December 4 – December 10)

About epidemiological week

Due to an influx of influenza laboratory reports this respiratory season, Manitoba Health is experiencing delays in the documentation of laboratory results within the provincial Public Health Information Management System (PHIMS). As s result, the influenza case counts for week 49 are lower than expected. We anticipate an update to these data in next week’s report.

Data extracted up to 1:00 am on December 15, 2022
Next reporting date: December 23, 2022


COVID-19 vaccination / Seasonal Influenza vaccination

COVID-19: Decreased Activity

COVID-19 activity in week 49 decreased from the previous week. COVID-19 associated hospital admissions continued to decrease this Week. Laboratory detection is substantively lower compared to the same time period in the previous two years. Older adults continue to be at higher risk for COVID-19 infections and associated hospital admissions and fatalities.

As of December 10, in all Manitoba residents, 78.0% have received at least two doses of COVID-19 vaccines. Additionally, 21.3% have received at least one dose within the last six months.

Wastewater surveillance data by December 8 indicated sustained activity of COVID-19 in Winnipeg and Brandon that decreased in the last few weeks.

Cases

About cases

  • Cases this week: 154
  • Total cases: 6,635
More Analyses

Testing

About testing

This week

  • Average daily specimens: 327
  • Weekly positivity rate: 11.4%

Total

  • Tested people: 33,563
  • Population tested: 2.4%
  • Specimens tested: 51,571
  • Positivity rate: 20.8%
More Analyses

Severity

About associated severity

Severe outcomes this week

  • Hospital admissions: 59
    • ICU admissions3: 15
  • Deaths: 0

Total severe outcomes

  • Hospital admissions: 2,117
    • ICU admissions: 247
  • Deaths: 203
More Analyses

Outbreaks

About outbreaks

COVID-19 outbreaks this week

  • In long-term care facilities: 4
  • In hospitals: 3
  • In other settings: 0

Total COVID-19 outbreaks

  • In long-term care facilities: 172
  • In hospitals: 78
  • In other settings: 1
More Analyses

Seasonal Influenza: Similar Activity

Influenza activity in week 49 continued to be high, similar to the previous week. The case counts in week 49 were lower than expected as a result of delays in the documentation of laboratory results within PHIMS. This week, influenza A test positivity increased to 27.2%, higher than 21.5% that was observed nationally. At the national level, influenza A activity showed signs of decrease in the last two weeks. Overall, the start of increase in activity this season is earlier than would be expected for this time of year. The predominant circulating strain is influenza A (H3N2). Up to week 49 this season, children below the age of five years are at the highest risk for influenza infection. This age group accounted for 12% of all influenza cases and 20% of associated hospital admissions.

At the same time, other respiratory viruses continue to co-circulate. RSV test positivity increased to 5.4% in week 49 from 4.0% in the previous week.

Cases

Cases this week

  • Influenza A: 231
  • Influenza B: 0

Total cases

  • Influenza A: 1,701
  • Influenza B: <5
More Analyses

Testing

Influenza testing this week

  • Average daily specimens: 215
  • Influenza A positivity rate: 27.2%
  • Influenza B positivity rate: 0.0%

Other respiratory pathogens this week

  • RSV4 positivity rate: 4.0%
  • RSV detections: 82
More Analyses

Severity

Severe outcomes this week

  • Hospital admissions: 6
    • ICU admissions: 0
  • Deaths: 0

Total severe outcomes

  • Hospital admissions: 331
    • ICU admissions: 6
  • Deaths: 22
More Analyses

Outbreaks

Influenza outbreaks this week

  • Influenza A: 6
  • Influenza B: 0

Total influenza outbreaks

  • Influenza A: 27
  • Influenza B: 0
More Analyses

Syndromic Indicators: Similar Activity

Though the activity level in all syndromic indicators increased indicating an increase in respiratory activity in the community and in primary care from late October, in week 49, activity in two syndromic indicators decreased from week 48.

Additionally, the daily respiratory related visits to emergency departments/urgent care continued to decrease in week 49 from week 47. However, the number of respiratory visits in young children especially those below the age of five years and the number of consequent hospital admissions continued to increase from early November.

FluWatchers

About FluWatchers

Participants reporting this week: 559

Reporting fever and cough: 3.4%

More Analyses

Physician Visits

About sentinel physicians

Influenza Like Illness (ILI) Visits to sentinel physicians this week: 4.4%

More Analyses

Antiviral

About Antiviral

Units of antiviral dispensed from pharmacies this week: 19

More Analyses

ED Visits

About emergency room visits

Respiratory visits to emergency department (ED) this week: 2209

More Analyses

Important Notes

  1. Data about COVID-19 and 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 become available. Cumulative totals include all events from start of the current season to end of the reporting week.
  3. ICU admissions were included in hospital admissions, and include adult and pediatric cases.
  4. RSV - Respiratory syncytial virus.

COVID-19

Cases

Figure 1. Weekly Cases of COVID-19 by Season, Manitoba, 2020 – 2022 (July through June)

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Figure 2. Sex and Age Distribution of COVID-19 Cases, Manitoba, July 3, 2022 – December 10, 2022

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Figure 3. Incidence Rate (/10,000 Population) of COVID-19 Cases by Age Group and Week of Public Health Report Date, Manitoba, July 3, 2022 – December 10, 2022

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Figure 4. Cases of COVID-19 by Health Region and Public Health Report Date, Manitoba, August 1, 2022 – December 10, 2022

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Table 1. Cases of COVID-19 and Incidence Rate (/10,000 population) by Health Region, Manitoba, July 3, 2022 – December 10, 2022

Helath region Total cases Cases this week Incidence rate this week Age-standardized incidence rate* this week
Winnipeg RHA 3952 102 1.3 1.3
Southern Health-Santé Sud 633 13 0.6 0.7
Interlake-Eastern RHA 706 12 0.9 0.8
Prairie Mountain Health 883 13 0.7 0.7
Northern Health Region 459 14 1.8 2.2

Note: * Age-standardized rates are used to account for differences in the age structure in health regions. The whole Manitoba population is used as the standard population.

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Testing

Figure 5. Average Daily Testing Volume and Positivity (%) for COVID-19 by Week of Specimen Receiving Date, Manitoba, July 3, 2022 – December 10, 2022

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Severity

Figure 6. Severe Outcomes of COVID-19 by Week of Outcome Date, Manitoba, July 3, 2022 – December 10, 2022

Note. ICU admissions are not included in the hospital admissions.

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Figure 7. Age Distribution of Severe COVID-19 Cases This Week Compared to All Cases, Manitoba, July 3, 2022 – December 10, 2022

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Outbreaks

Figure 8. Weekly COVID-19 Outbreaks, Manitoba, 2020 – 2022

Note: All respiratory outbreaks include COVID-19 outbreaks, influenza outbreaks and the other respiratory outbreaks with known or unknown pathogens.

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Vaccination

Table 2. Coverage of COVID-19 Vaccinations, Manitoba, December 10, 2022

Age group (years) At least 1 dose At least 2 doses At least 1 dose within the last 6 months At least 1 dose of Bivalent
.5-04 9.2% 3.5% 9.1% 0.0%
05-11 55.8% 42.6% 9.5% 0.1%
12-17 82.7% 78.1% 9.4% 5.0%
18-29 88.4% 85.3% 7.4% 6.0%
30-39 84.5% 82.0% 12.0% 10.6%
40-49 87.8% 86.0% 16.2% 14.5%
50-59 87.1% 85.7% 24.7% 18.3%
60-69 94.8% 93.5% 42.6% 32.8%
70-79 >=95.0% >=95.0% 56.2% 45.3%
80+ >=95.0% >=95.0% 56.1% 47.3%
ALL 81.3% 78.0% 21.3% 15.9%

For more information, please visit COVID-19 vaccination coverage in Canada - Canada.ca

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Seasonal Influenza

Cases

Figure 9. Weekly Cases of Influenza by Season, Manitoba, 2019 – 2022 (July through June)

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Figure 10. Incidence Rate (/10,000 Population) of Influenza Cases by Age Group and Week of Public Health Report Date, 2018 – December 10, 2022

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Table 3. Cases of Influenza and Incidence Rate (/10,000 population) by Health Region, Manitoba, July 3, 2022 – December 10, 2022

Helath region Total cases Cases this week Incidence rate this week Age-standardized incidence rate* this week
Winnipeg RHA 826 113 1.4 1.4
Southern Health-Santé Sud 228 35 1.6 1.6
Interlake-Eastern RHA 266 31 2.3 2.3
Prairie Mountain Health 290 38 2.2 2.1
Northern Health Region 77 11 1.4 1.8

Note: * Age-standardized rates are used to account for differences in the age structure in health regions. The whole Manitoba population is used as the standard population.

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Table 4. Antiviral Susceptibility of Isolates by Influenza Type and Subtype, Canada, September 1 – December 15, 2022

Oseltamivir
Zanamivir
Resistant Susceptible Resistant Susceptible
Canada A(H3N2) 0 112 112
A(H1N1) 0 10 10
Manitoba A(H3N2) 0 84 85
A(H1N1) 0 8 8
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Table 5. Strain Characterization of Influenza Isolates, Canada, September 1 – December 15, 2022

Strain
Isolates
Canada Manitoba
Influenza A (H3N2)/Darwin/6/2021-like 122 94
Influenza A (H1N1)/Wisconsin/588/2019-like 12 10

Notes: A/Darwin/6/2021-like virus is the H3N2 virus selected for the 2022/23 Northern Hemisphere Influenza vaccine. A/Wisconsin/588/2019-like virus is the recommmended H1N1 component for the 2022-2023 Northern Hemisphere influenza vaccine.

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Testing

Figure 11. Average Daily Testing Volume and Positivity (%) for Influenza by Week of Specimen Receiving Date, Manitoba, July 3, 2022 – December 10, 2022

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Figure 12. Number of Positive Respiratory Virus Tests by Week of Specimen Receiving Date, Manitoba, July 3, 2022 – December 10, 2022

Note. Other respiratory viruses include adenovirus, enterovirus/rhinovirus, human coronavirus (seasonal), human metapneumovirus and human parainfluenza virus.

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Severity

Figure 13. Severe Outcomes of Influenza by Week of Outcome Date, Manitoba, July 3, 2022 – December 10, 2022

Note. ICU admissions are not included in the hospital admissions.

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Figure 14. Age Distribution of Severe Influenza Cases in All Cases, Manitoba, July 3, 2022 – December 10, 2022

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Outbreaks

Figure 15. Weekly Respiratory and Influenza Outbreaks, Manitoba, 2019 – December 10, 2022

Note: All respiratory outbreaks include COVID-19 outbreaks, influenza outbreaks and the other respiratory outbreaks with known or unknown pathogens.

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Vaccinations

Table 7. Coverage of Influenza Vaccinations, Manitoba, September 1, 2022 – December 10, 2022

Age group Does Coverage percentage
0-4 11437 13.5%
5-17 28741 12.6%
18-49 78699 13.3%
50-64 71709 27.7%
65+ 133787 57.2%
All 326842 23.4%

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FluWatchers

Figure 16. Weekly FluWatchers Participants and Percentage Reporting Fever and Cough, Manitoba, 2019 – December 10, 2022

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Physician Visits

Figure 17. Weekly Percentage of ILI Related Visits to Sentinel Physicians, Manitoba, 2018 – December 10, 2022

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Antiviral

Figure 18. Weekly Units of Antiviral Dispensed from Pharmacies, Manitoba, 2018 – December 10, 2022

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ED Visits

Figure 19. Weekly Respiratory Visits to Emergency Department, Manitoba, 2017 – December 10, 2022

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