Weekly influenza reports

March 5, 2023 to March 18, 2023 (weeks 10-11)

• At the national level, influenza activity remains low at levels typically seen in late spring/early summer. Influenza activity continues to be reported in most provinces.

Virologic

• In week 11, the percentage of tests positive for influenza was 1.6% and a total of 392 laboratory detections (268 influenza B and 124 influenza A) were reported. Influenza B detections (68%) are predominant.
• Among subtyped influenza A detections in week 11, 74% (23) were influenza A(H1N1).

Syndromic

• The percentage of visits for influenza-like illness (ILI) was 0.8% in week 11. The percentage of visits for ILI is within levels typical of this time of year.
• The percentage of FluWatchers reporting fever and cough was 1.4% in week 11, below levels typical of this time of year.

Outbreaks

• From August 28, 2022 to March 18, 2023 (weeks 35 to 11), 600 laboratory-confirmed influenza outbreaks have been reported (one laboratory-confirmed influenza outbreak was reported in week 11).

Severe Outcomes

• The highest cumulative hospitalization rate up to week 11 is among adults 65 years of age and older (133/100,000 population) and children under 5 years of age (124/100,000 population). The overall cumulative hospitalization rate this season to date is 48/100,000 population.

Other Notes

• The next scheduled report (weeks 12-13) will be published April 11, 2023.
• Weekly reporting of laboratory detections of influenza, SARS-CoV-2, and other seasonal respiratory viruses will continue via our Respiratory Virus Detections Surveillance System.