How Do Flu Vaccines Work
Flu vaccines cause antibodies to develop in the body about two weeks after vaccination. These antibodies provide protection against infection with circulating influenza viruses.
Seasonal flu vaccines are designed to protect against the influenza viruses that research indicates will be most common during the upcoming season. All flu vaccines in the United States are quadrivalent vaccines, which means they protect against four different flu viruses: an influenza A virus, an influenza A virus, and two influenza B viruses.
Can I Get The Flu From The Flu Vaccine
No. The virus thats in the flu vaccine is either dead or for FluMist Quadrivalent extremely weak. Because of this, flu vaccines are unable to cause the flu. However, some people experience flu-like symptoms in the days that follow their vaccine. These are side effects of the flu vaccine, and its a sign your immune system is learning how to fight the flu virus.
After your flu vaccine, you may experience:
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A sore, red, or swollen arm
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A headache
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Muscle aches
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Tiredness
Remember, these are expected side effects and dont mean youre getting sick with the flu. They should go away within a few days.
Unfortunately, its still possible to get sick with the flu after youve received your flu vaccine. It takes about 2 weeks after your vaccine for your immune system to protect you fully. So its possible to catch the flu during that time. And as mentioned earlier, flu vaccine effectiveness isnt perfect. Its also possible to get sick with a strain that wasnt included in the vaccine.
Can Severe Problems Occur
Life-threatening allergic reactions to flu shots are very rare. Signs of serious allergic reaction can include breathing problems, hoarseness or wheezing, hives, paleness, weakness, a fast heartbeat, or dizziness. If they do occur, it is usually within a few minutes to a few hours after receiving the shot. These reactions can occur among persons who are allergic to something that is in the vaccine, such as egg protein or other ingredients. While severe reactions are uncommon, you should let your doctor, nurse, clinic, or pharmacist know if you have a history of allergy or severe reaction to influenza vaccine or any part of flu vaccine.
There is a small possibility that flu vaccine could be associated with Guillain-Barré syndrome, generally no more than 1 or 2 cases per million people vaccinated. This is much lower than the risk of severe complications from flu, which can be prevented by flu vaccine.
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Is The Flu Vaccine Safe
Yes. Flu vaccines have been used for over 50 years and have been safely given to hundreds of millions of people, including pregnant people. Flu vaccines, like all vaccines used in the U.S., are carefully monitored for safety through the U.S. vaccine monitoring systems .
Find answers to more questions about vaccine safety.
What Vaccines Are Available For The 2021

There are nine vaccines that have been approved and released by the FDA for the 2021-2022 flu season. This year, all FDA-approved flu vaccines are quadrivalent meaning they protect against four different strains of influenza . Heres a rundown of the available flu vaccines for the year.
Vaccine name | |
---|---|
Intramuscular | Egg protein |
Its important to note that pharmacies and healthcare providers may only carry a few brands of flu vaccine not all nine that are FDA-approved. If you are interested in or know you need a certain flu vaccine, its best to call ahead and see if your preferred vaccine is available.
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What Are The Expected Side Effects Of The Flu Vaccine
Common side effects following the influenza vaccination include pain, redness and swelling at the injection site as well as fever, malaise and myalgia. Symptoms usually occur within the first 24-48 hours. Cell-based influenza vaccines have a similar side-effects profile as traditional egg-based influenza vaccines. Following immunisation with adjuvanted quadrivalent formulations, side effects may occur slightly more commonly than with standard QIV formulations.
Is There Anyone Who Shouldn’t Get The Flu Shot
Block said that since influenza vaccines are “dead,” or don’t contain any live virus, people who are immunocompromised or pregnant can safely take them. If you have an allergy to an ingredient in the vaccine, talk to your doctor.
Children under the age of 6 months should not get the flu vaccine. Anyone currently experiencing a fever should not get a flu vaccine until their symptoms stop.
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What Should I Do If I Think I Am Getting The Flu
Stay home, rest, and avoid contact with others except to get medical care if needed, experts say. Avoid contact with others for at least 24 hours after the fever subsides to avoid spreading the flu.
Be on the lookout for emergency warning signs that you may be getting serious flu-related complications.
In children, these include:
- Symptoms that improve but then return with a fever and worsening cough.
Ii5 Choice Of Seasonal Influenza Vaccine
The decision to include specific influenza vaccines as part of publicly funded provincial and territorial programs depends on several factors, such as cost-effectiveness evaluation and other programmatic and operational factors, such as implementation strategies. Not all products will be made available in all jurisdictions and availability of some products may be limited therefore, officials in individual provinces and territories should be consulted regarding the products available in individual jurisdictions.
With the availability of influenza vaccines that are designed to enhance immunogenicity in specific age groups or given through a different route of administration, the choice of product has become more complex.
Choice of influenza vaccine by age group
Recommendations for individual-level decision making
- NACI recommends that influenza vaccine should be offered annually to anyone 6 months of age and older who does not have contraindications to the vaccine. Table 2 provides age group-specific recommendations for the age-appropriate influenza vaccine types authorized for use in Canada.
Recommendations for public health program-level decision making
- NACI recommends that any of the age-appropriate influenza vaccine types available for use may be considered for people without contraindications to the vaccine. Table 2 provides age group-specific recommendations for the age-appropriate influenza vaccine types authorized in Canada.
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The Best Flu Vaccine For People Over 65
As we get older, our immune systems have a harder time responding to illnesses and vaccines. To help provide better protection, there are a few recommended options for older adults this year:
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Fluzone High-Dose Quadrivalent also known as the high-dose flu shot
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Fluad Quadrivalent
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Flublok Quadrivalent
If one of these three vaccines isnt available, you should still get vaccinated with another flu vaccine thats FDA-approved for your age range. All flu vaccines are effective against the flu. Its better to be vaccinated than to try to wait for a particular flu vaccine to become available.
The Best Flu Vaccine If You Have Egg Allergies
Many flu vaccines are made using chicken eggs called egg-based vaccines. While most people with egg allergies are still able to receive egg-based flu vaccines, there are rare instances where they can cause life-threatening allergic reactions. If this is the case for you or if youre concerned, Flucelvax Quadrivalent and Flublok Quadrivalent are two egg-free flu vaccine options.
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When To Get The Flu Shot
Flu season typically runs from late fall to early spring.
Flu shots are now available for all Ontarians. You should get a flu shot as soon as possible because it takes two weeks to take effect.
The National Advisory Committee on Immunization now recommends that COVID-19 vaccines may be given at the same time as the flu vaccine.
Talk to your doctor or pharmacy to learn more.
Why Are Adjuvanted Formulations Of Influenza Vaccine The Preferred Vaccine For Those 65 Years

A gradual decline of the immune system occurs as people age , impacting how the immune system responds to immunisation. For adults aged 65 years the adjuvanted QIV, Fluad® Quad is preferentially recommended over standard QIVs as the antibody response is increased in comparison to non-adjuvanted QIV influenza vaccines.
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When Will The 2021 Flu Vaccine Become Available
The Annual Influenza Immunisation Programme will have a fixed start date of 1 April. In previous years the programme started as soon as the influenza vaccine became available, generally by early March. The change to a fixed start date of 1 April is intended to ensure that the vaccine remains as effective as possible during the peak incidence of influenza, which in recent years has occurred in late winter. For further information, see the Ministry of Health Policy Statement
What Is The Super Flu Shot
TODAY’s Al Roker commented that since he is over 65, he received a high-dose version of the flu shot. The high-dose flu vaccines are intended to give people 65 and older better protection against the flu.
“The reason that we do that in older people is because when we get older we are not able to amount as robust an immune response,” Azar said.
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Why Do Some People Not Feel Well After Getting A Flu Shot
Flu vaccine side effects are generally mild and go away on their own within a few days. Some side effects that may occur from a flu shot include soreness, redness, and/or swelling where the shot was given, headache , fever, nausea, muscle aches, and fatigue. The flu shot, like other injections, can occasionally cause fainting.
How Do Experts Decide What To Put Into The Flu Vaccine
During flu season, experts study samples of the viruses circulating to find out how well the vaccine protected against those viruses. They use that information to help make their decision for the next one.
In general, vaccines work better against influenza B and influenza A viruses than they do against influenza A viruses.
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Iii1 People At High Risk Of Influenza
All pregnant women
NACI recommends the inclusion of all pregnant women, at any stage of pregnancy, among the particularly recommended recipients of IIV, due to the risk of influenza-associated morbidity in pregnant womenFootnote 25,Footnote 26,Footnote 27,Footnote 28,Footnote 29, evidence of adverse neonatal outcomes associated with maternal respiratory hospitalization or influenza during pregnancyFootnote 30,Footnote 31,Footnote 32,Footnote 33, evidence that vaccination of pregnant women protects their newborns from influenza and influenza-related hospitalizationFootnote 34,Footnote 35,Footnote 36,Footnote 37, and evidence that infants born during influenza season to vaccinated women are less likely to be premature, small for gestational age, and of low birth weight than if born to women that had not received an influenza vaccineFootnote 38,Footnote 39,Footnote 40,Footnote 41. The risk of influenza-related hospitalization increases with length of gestation .
Refer to the Statement on Seasonal Influenza Vaccine for 2011-2012 and the Statement on Seasonal Influenza Vaccine for 2012-2013 for further details on influenza vaccination during pregnancy.
Adults and children with chronic health conditions
Neurologic or neurodevelopment conditions
People of any age who are residents of nursing homes and other chronic care facilities
Adults 65 years of age and older
All children 6-59 months of age
Indigenous peoples
When Is The Best Time To Get A Flu Shot
And as flu shots roll out, some experts suggest getting them sooner than later. While Davidson sticks to a motto of better late than never, she added ideally you want to try to achieve immunization in the fall.
It takes your body two weeks to establish an immune response to the vaccine and to make it effective against the flu.
In other words, the sooner you get it, the more protected you will be in the long-run especially because flu season tends to wind down in the spring.
Davidson added while the virus may not be a severe health risk to everyone, some populations are much higher at risk. Babies , children with developing immune systems, pregnant women, seniors and anyone with a chronic health condition are most at risk.
Complications from the flu can include pneumonia, the government of Ontario noted, and flu cases cause about 3,500 deaths in Canada every year.
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Seasonal Influenza Vaccine Supply & Distribution
Note: Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices United States, 2021-2022 Influenza Season has been . More information on the 2021-2022 season is also available.
Influenza viruses change from year to year, so influenza vaccines must be updated annually to include the viruses that will most likely circulate in the upcoming season. Once the viruses are selected for the new formulation, private manufacturers produce, test, release and distribute influenza vaccine.
Iv2 Live Attenuated Influenza Vaccine

LAIV contains standardized quantities of FFU of live attenuated influenza virus reassortants. The virus strains in LAIV are cold-adapted and temperature sensitive, so they replicate in the nasal mucosa rather than the lower respiratory tract, and they are attenuated, so they do not produce ILI. There have been no reported or documented cases, and no theoretical or scientific basis to suggest transmission of vaccine virus would occur to the individual administering LAIV. As a live replicating whole virus formulation administered intranasally, it elicits mucosal immunity, which may more closely mimic natural infection.
Vaccine currently authorized for use:
- FluMist® Quadrivalent
Efficacy and effectiveness
After careful review of the available Canadian and international LAIV VE data over many influenza seasons, NACI concluded that the current evidence is consistent with LAIV providing comparable protection against influenza to that afforded by IIV and does not support a recommendation for the preferential use of LAIV in children 2-17 years of age.
Refer to the Statement on Seasonal Influenza Vaccine for 2018-2019 for detailed information supporting this recommendation.
Immunogenicity
LAIV4 has shown non-inferiority based on immunogenicity compared to LAIV3 in both children and adults. The immune response to the B strain found only in the quadrivalent formulation was better in children who received the quadrivalent vaccine Footnote 158, Footnote 159, Footnote 160.
Safety
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Rapid Response To Pandemic Flu
The rapid development, production, and distribution of pandemic influenza vaccines could potentially save millions of lives during an influenza pandemic. Due to the short time frame between identification of a pandemic strain and need for vaccination, researchers are looking at novel technologies for vaccine production that could provide better “real-time” access and be produced more affordably, thereby increasing access for people living in low- and moderate-income countries, where an influenza pandemic may likely originate, such as live attenuated technology and recombinant technologies . As of July 2009, more than seventy known clinical trials have been completed or are ongoing for pandemic influenza vaccines. In September 2009, the FDA approved four vaccines against the 2009 H1N1 influenza virus , and expected the initial vaccine lots to be available within the following month.
In January 2020, the US Food and Drug Administration approved Audenz as a vaccine for the H5N1 flu virus. Audenz is a vaccine indicated for active immunization for the prevention of disease caused by the influenza A virus H5N1 subtype contained in the vaccine. Audenz is approved for use in persons six months of age and older at increased risk of exposure to the influenza A virus H5N1 subtype contained in the vaccine.
Why Do You Need An Annual Flu Shot
Unlike some other vaccines that have a longer protection period, flu shots are required every year to ensure proper protection. Your immune response and protection from vaccination will weaken over time, so a yearly vaccine for a common virus is the best choice to protect yourself. Plus, flu viruses change all the time, and vaccines are often updated to better protect against upcoming viruses. If you want the best protection for you and your family, then you should prioritize flu shots every year.
If you want to get a flu shot, you can head to your local flu shots clinic in Suwanee, GA. Visit the trusted team at Gwinnett Urgent Care to take care of your flu shots and answer any questions you have about the flu.
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Remind Me Why Get A Flu Shot Each Year
Influenza viruses change each year and the vaccine is updated to keep up with these changes. This year, for example, the vaccine protects against two different strains than the 2018 vaccine.
Our bodys immune response to the vaccine also wanes over time. So even if you were vaccinated last winter, you may no longer be fully protected 18 months later, depending on your age and your response to the last vaccination.
What Kinds Of Flu Vaccines Are Available
CDC recommends use of any licensed, age-appropriate influenza vaccine during the 2021-2022 influenza season. Available influenza vaccines include quadrivalent inactivated influenza vaccine , recombinant influenza vaccine , or live attenuated influenza vaccine . No preference is expressed for any influenza vaccine over another.
Quadrivalent flu vaccines include:
Are any of the available flu vaccines recommended over others?
For the 2021-2022 flu season, the Advisory Committee on Immunization Practices recommends annual influenza vaccination for everyone 6 months and older with any licensed, influenza vaccine that is appropriate for the recipients age and health status, including inactivated influenza vaccine , recombinant influenza vaccine , or live attenuated nasal spray influenza vaccine with no preference expressed for any one vaccine over another.
There are many vaccine options to choose from, but the most important thing is for all people 6 months and older to get a flu vaccine every year. If you have questions about which vaccine is best for you, talk to your doctor or other health care professional.
Who Should Vaccinate?
Everyone 6 months of age and older should get an influenza vaccine every season with rare exception. CDCs Advisory Committee on Immunization Practices has made this recommendation since the 2010-2011 influenza season.
More information is available at Who Needs a Flu Vaccine.
Who Should Not Be Vaccinated?
When should I get vaccinated?
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