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Updated: November 1, 2020

What are the risks and benefits of getting a flu shot during the COVID-19 pandemic?

Summary

The following is a brief summary of evidence that provides high quality information on the risks and benefits of receiving the flu shot during the COVID-19 pandemic. For additional information about each of the sources, see the Table below.    For additional information about each of the sources, see the Table below.

The Centers for Disease Control and Prevention (CDC) notes in its guidance, What are the benefits of flu vaccination? ,that receiving the flu vaccine this year is more important than ever [4].  The Government of Canada and the CDC state that receiving the flu vaccine will provide the following benefits to both individuals and their communities: 1) reduce the influenza-associated burden on healthcare systems that are needed to treat patients with COVID-19; 2) reduce the risk of illness, hospitalization and death in influenza patients among children, working adults and older adults; 3) save healthcare resources that can be diverted to care for COVID-19 patients; 4) protect people who haven’t gotten the flu vaccine, by reducing overall flu transmission in the community [3,4]. Therefore, in its Guidance on the use of influenza vaccine in the presence of COVID-19, the Government of Canada recommends that the influenza vaccine should be given to everyone who is 6 months of age or older and who does not have severe reactions to the vaccine [3].  
 
The authors of Viral and atypical co-infections in COVID-19: a systematic review and meta-analysis state that COVID-19 patients with co-infections during influenza season had higher hospitalization rates and greater disease severity [1].While the authors of the Influenza Vaccination and COVID19 Mortality in the USA study describe that rates of COVID-19 death are lower in elderly populations in areas where influenza immunization is high, this is an area of ongoing research and the results of a single study are not conclusive [7]. The hypothesis that the influenza vaccine increases the risk of SARS-CoV-2 infection is not supported by current evidence or  by Government of Canada guidance [3]. The Coronavirus or Other Non-influenza Respiratory Viruses: Retrospective Analysis From Canada, 2010-2011 to 2016-2017 study states that the influenza vaccine can reduce the risk of acquiring an influenza illness by greater than 40%, but has no effect on acquiring coronaviruses or other non-influenza respiratory viruses [6].  
 
In the Canadian Immunization Guidance Chapter on Influenza and Statement on Seasonal Influenza Vaccine for 2020-2021, the Government of Canada identified indicated the following groups of vulnerable people for whom the influenza vaccine is particularly recommended: 1) pregnant women; 2) those with co-morbidities or receiving treatment that makes them immunocompromised; 3) long-term care residents and staff; 4) children between the ages of 6 months and 59 months; 5) Indigenous people; and 6) those who engage closely with any of these high-risk groups [2]. The Province of Ontario indicates in its The flu guidance where and by whom flu vaccinations can be administered [5]. This guidance recommends that those 6 months to 4 years old should get their flu vaccine through their doctor or nurse practitioner or where available at local public health units, and those 5 years and older should get it from any of the above, or at participating pharmacies [5]. It is also important to note that the flu shot takes approximately two weeks to take effect and that the flu virus in circulation changes each year with the vaccine to match the particular strain, so it is therefore recommended to receive the flu shot each year [5]

Evidence

What‘s Trending on Social Media and Media

FluShot is a trending topic on Twitter in Canada. Dr. Theresa Tam, the Chief Public Health Officer of Canada, participated in the trend by stating the importance of getting the vaccine during the COVID-19 pandemic. 

 
With the high demand for flu shots this year, this CP24 News article says that Ontario has ordered 5.1 million flu vaccine doses, a 16% increase from last year, as a plan to protect the healthcare system from a possible increase in hospitalizations related to the second wave of COVID-19. The government has also set aside $26.5 million to purchase additional flu vaccine doses, if required. 
 
The Global News released an article on the strong interest amongst parents for the flu shot. The flu shot is crucial for children aged 0 to 2 years old, as toddlers and younger school-aged children are the largest spreaders of the flu. A group representing more than 1,400 Ontario pediatricians says 30 to 35% of the population typically get the flu shot each year, but is urging all Canadians to get vaccinated. 

Organizational Scan

Michael Garron Hospital highlights the importance of the flu shot to decrease the risk of overwhelming the healthcare systems and prevent serious, potentially life-threatening illnesses in individuals. The flu and COVID-19 share some symptoms, including fever, cough, headache, and fatigue making it difficult to determine which one of the two viruses someone may be suffering from without a test [8]

The York Region released information on the flu shot to protect members of the public, and the health care systems currently responding to the COVID-19 pandemic. The flu shot will be available in York Region Public Health Immunization Clinics between October 2020 and January 2021. Access information about where to get flu shot in York Region here. Toronto Public Health has created an appointment booking system for flu shots. The website provides locations of flu vaccination clinics in Toronto [9,10,11]

Review of Evidence

Resource Type/Source of Evidence Last Updated
Viral and atypical co-infections in COVID-19: a systematic review and meta-analysis
— Davis et al.
Meta-Analysis

This meta-analysis notes that disease severity and hospitalization rates were higher among COVID-19 patients with co-infections compared to those with no coinfection. Among hospitalized COVID-19 cases, 11.6% of them also had a respiratory co-infection It is likely that an influenza co-infection is a result of a large proportion of the measured co-pathogens based on the timing of the study and seasonality of influenza illnesses.  

Last Updated: June 18, 2020
Canadian Immunization Guidance Chapter on Influenza and Statement on Seasonal Influenza Vaccine for 2020-2021
— Government of Canada
National Guidance

The Government of Canada notes that the influenza vaccine is particularly recommended to the following people: 1) pregnant women; 2) adults and children with co-morbidities or receiving treatment that makes them immunocompromised; 3) residents and staff in a long-term care home; 4) older adults; 5) children between 6 and 59 months of age; 6) Indigenous people; and 7) those who work or interact closely with high-risk populations.   

Last Updated: October 14, 2020
Guidance on the use of influenza vaccine in the presence of COVID-19
— Government of Canada
National Guidance

This guidance states that the influenza vaccine should be given to everyone who is 6 months of age or older and who does not have contraindications to the vaccine. The hypothesis that influenza vaccine increases the risk of SARS-CoV-2 infection is not supported by the current evidence. The influenza vaccine is a tool to reduce influenza-association burden on healthcare systems, which is even more important this year due to the COVID-19 pandemic.  

Last Updated: September 28, 2020
What are the benefits of flu vaccination?
— CDC: Centers for Disease Control and Prevention
National Guidance

The CDC notes that receiving the flu vaccine during 2020-2021 is more important than ever. As the flu virus and COVID-19 will both spread this fall and winter, healthcare systems could be overwhelmed from treating both flu and COVID-19 patients. Receiving the flu vaccine has been shown to reduce the risk of illness, hospitalization and death among influenza patients among children, working adults and older adults. It will also save healthcare resources that can be therefore be diverted to care for COVID-19 patients. Getting vaccinated will also protect people who haven’t gotten the flu vaccine, by reducing overall flu transmission in the community. 

Last Updated: October 6, 2020
The flu
— Government of Ontario
Provincial Guidance

This guidance states that everyone 6 months and older should get their flu shot and to get it early. Those 6 months to 4 years old should get their flu vaccine through their doctor or nurse practitioner or some local public health units. Those 5 years and older should get it from a doctor or nurse practitioner, some local public health units or participating pharmacies. Flu shot takes approximately two weeks to take effect. The flu circulating changes each year and therefore receiving the flu shot is recommended each year.  

Last Updated: October 14, 2020
Coronavirus or Other Noninfluenza Respiratory Viruses: Retrospective Analysis From Canada, 2010-2011 to 2016-2017
— Skowronski et al.
Single Study

This study finds that having received the influenza vaccine reduced the risk of acquiring an influenza illness by >40%, but had no effect on coronaviruses or other non-influenza respiratory viruses. Therefore, the influenza vaccine does not increase the risk of any coronavirus illness.  

Last Updated: May 21, 2020
Influenza Vaccination and COVID19 Mortality in the USA
— Zanettini et al.
Single Study

This study states that in areas where influenza immunization uptake is high, there are lower rates of COVID-19 death in elderly populations. Although more research is needed to confirm these findings, it is suggested that an influenza vaccination decreases COVID-19 mortality in the elderly population.  

Last Updated: June 25, 2020
Flu Season During COVID-19: Why getting the flu vaccine is more important than ever this year
— Michael Garron Hospital
Organizational Scan Last Updated: October 15, 2020
Flu Shot Information
— York Region
Organizational Scan Last Updated: November 1, 2020
Flu Shot Clinics- seasonal flu – when and where to get your flu shot
— Toronto Public Health
Organizational Scan Last Updated: November 1, 2020
TPH Appointment Booking System
— Toronto Public Health
Organizational Scan Last Updated: November 1, 2020
Disclaimer: The summaries provided are distillations of reviews that have synthesized many individual studies. As such, summarized information may not always be applicable to every context. Each piece of evidence is hyperlinked to the original source.

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