Question Period Note: Seasonal Influenza

N/A

Canada experienced a short and very intense seasonal influenza epidemic in the fall and early winter of 2022.
Influenza activity is currently within inter-seasonal levels, and it remains unknown whether Canada will experience another period of elevated influenza activity during the remainder of winter and spring 2023.
Key Messages
• The health and safety of Canadians is the Government’s top priority.
• The flu vaccine is the most effective way to prevent the flu and flu-related complications, such as pneumonia. That is why the Government of Canada works with the provinces and territories to provide flu vaccines to Canadians every year during flu season.
• Getting the flu vaccine not only protects you—it also helps protect your family and friends, young and old, your community, and especially those at higher risk of flu-related complications.
• The National Advisory Committee on Immunization (NACI) recommends that everyone 6 months of age and older get the annual flu vaccine, especially people at high-risk of complications from the flu and people who can pass on the flu virus to those at high risk.

If pressed on concurrent administration with COVID-19 vaccine
• NACI currently recommends that all seasonal flu vaccines may be given concurrently (i.e., same day, or at any time before or after) with COVID 19 vaccines for individuals 6 months of age and older.

Annual Seasonal Influenza Campaign
The Public Health Agency of Canada’s (PHAC) seasonal influenza campaign aims to dispel myths about the seasonal flu vaccine and promote the uptake of the flu vaccine and other public health measures to help Canadians protect themselves and others.

Influenza Surveillance
Canada participates in national and international activities to detect and monitor the spread of influenza in humans and animals. PHAC maintains FluWatch, Canada’s national surveillance system that monitors circulating flu viruses, activity levels, outbreaks, and hospitalizations.

Low seasonal influenza circulation occurred while stringent COVID-19 public health measures were in place since the spring of 2020. With increased reopening, community circulation of seasonal influenza occurred in the spring of 2022 and persisted until June
2022.

Influenza Vaccine Development and Supply
The World Health Organization issues recommendations each year on the composition of the influenza vaccines for the southern and northern hemispheres. These recommendations are used by national vaccine regulatory agencies and pharmaceutical companies to develop, produce and license seasonal influenza vaccines.

The provinces and territories (P/Ts) and some federal departments (Indigenous Services Canada, Correctional Service of Canada, Global Affairs Canada, Royal Canadian Mounted Police, and Department of National Defence) order the majority of their influenza vaccine through Public Services and Procurement Canada’s Bulk Procurement Program. The P/Ts use their discretion to make decisions regarding their influenza vaccination programs, including eligible populations, vaccine types and quantities.

Collectively, initial federal and P/T (F/P/T) demand amounted to approximately 15 million doses of influenza vaccine for the 2022-2023 influenza season, which is a decrease of ~15% from the 2021-2022 season (17.6 million doses) and is ~6% lower than the total number of doses actually delivered in the 2020-2021 season (16 million doses). However, this is still an increase from pre-COVID seasons when F/P/T demand was in the range of 11-12 million doses per year.

Similar to the past two years, PHAC has also purchased and paid for 330,000 doses of Fluzone® High-Dose (HD) from Sanofi Pasteur to vaccinate all eligible residents (65 years of age and above) in Long Term Care facilities in all P/T jurisdictions. Fluzone® HD is a split virus, high-dose quadrivalent vaccine indicated for adults aged 65 years and older, that contains four times the antigen of standard influenza vaccines. Evidence suggests that Fluzone® HD provides better protection to older adults. PHAC’s Fluzone® HD doses are included in the 15 million dose total F/P/T order.

Given the potential for a substantial influenza season in 2022-2023, PHAC purchased an additional 715,000 doses of influenza vaccine (inclusive of the 15 million total orders) as part of a reserve to be used by P/Ts if their ordered quantity proves insufficient. Given widespread influenza activity earlier in the 2022-2023 season, there was increased demand from F/P/T jurisdictions for seasonal influenza vaccines. To date, F/P/T jurisdictions ordered additional influenza vaccine doses above the initial 15 million dose demand, totalling approximately 400K doses—all of which were completed through existing contracts under the Bulk Procurement Program. As of December 2022, all seasonal influenza vaccines ordered by F/P/T jurisdictions have been delivered in full.

Flu Vaccination Coverage
The Seasonal Influenza Vaccination Coverage Survey collects information every year about the uptake of the influenza vaccine in Canada. Each flu season, this survey is used to estimate coverage among all adults, as well as among individuals at higher risk of complications including seniors aged 65 years and older and adults aged 18-64 years with chronic medical conditions.

In the 2021/22 flu season:
• Overall, influenza vaccination coverage among all adults (39%) was similar to the previous seasons (42% in 2019/20 and 40% in 2020/21);
• Only 38% of Canadian adults aged 18-64 years with chronic medical conditions received an influenza vaccine;
• Vaccination coverage among seniors (71%) is closer to the national goal of 80%; however, no improvement has been observed in the last 3 years.

In 2022, PHAC implemented the annual Childhood Covid-19 Immunization Coverage Survey which collects information about the uptake of the influenza vaccine among Canadian children younger than 18 years of age.

In the 2021/22 flu season:
• Overall, 30% of children 6 months-17 years received influenza vaccine.
• More children 6 months-4 years (40%) received their influenza vaccine compared to 5-11 (29%) or 12-17 (24%) year-olds.
• A higher percentage of children with a medical condition (36%) received their influenza vaccine compared to those without a medical condition (29%).

Recommendations for Influenza Vaccination
The National Advisory Committee on Immunization (NACI) recommends that everyone 6 months of age and older without contraindications receive an annual influenza vaccine.

Receiving the influenza vaccine will not provide protection from COVID-19, but it can reduce the chances of being co-infected with influenza and COVID-19 at the same time, a situation that can lead to serious complications. Preventing influenza will also help to reduce stress on the health care system during the ongoing COVID-19 pandemic.

Additional PHAC guidance on the administration of seasonal influenza vaccine in the context of the COVID-19 pandemic has been developed to support influenza vaccine programs and primary care providers in offering influenza vaccines this fall. This includes advice on who should receive the influenza vaccine, what to do if someone seeking vaccination is showing symptoms, and simultaneous administration of influenza vaccines with COVID-19 vaccines.

NACI currently recommends that all the seasonal influenza vaccines (including live and non-live vaccines) may be given concurrently with (i.e., same day) or at any time before or after, COVID 19 vaccines for individuals 6 months of age and older. This will help to facilitate influenza vaccine programs in the fall and winter months.

NACI will continue to monitor the evidence base, including ongoing and anticipated studies investigating influenza vaccines administered at the same time as, or any time before or after, COVID-19 vaccines and update its recommendations as needed.
 

• Influenza (flu) season in Canada usually occurs from mid-November to mid-May.
• During 2020/21 and 2021/22, while COVID-19 public health measures and travel restrictions were in place, seasonal circulation of the flu remained low both globally and in Canada.
• After the COVID-19 public health measures were reduced, Canada experienced a seasonal influenza epidemic in the spring and early summer of 2022.
• In the fall of 2022, Canada experienced a short and very intense influenza epidemic that lasted from mid-October to mid-November.
• For the week ending January 14, 2023, the percentage of tests positive for influenza was 2.3%, well below expected levels for this time of year.
• In a typical year in Canada, seasonal influenza leads to an estimated average of 12,200 hospitalizations and 3,500 deaths.