How Effective Is The Seasonal Flu Shot
Influenza vaccine effectiveness can vary. The protection provided by a flu vaccine varies from season to season and depends in part on the age and health status of the person getting the vaccine and the similarity or match between the viruses in the vaccine and those in circulation. During years when the flu vaccine match is good, it is possible to measure substantial benefits from flu vaccination in terms of preventing flu illness and complications. However, the benefits of flu vaccination will still vary, depending on characteristics of the person being vaccinated , what influenza viruses are circulating that season and, potentially, which type of flu vaccine was used. For more information, see Vaccine Effectiveness How well does the Flu Vaccine Work. For information specific to this season, visit About the Current Flu Season.
*References for the studies listed above can be found at Publications on Influenza Vaccine Benefits. Also, see the A Strong Defense Against Flu: Get Vaccinated! fact sheet.
Flu Vaccine And Coronavirus
Flu vaccination is important because:
- more people are likely to get flu this winter as fewer people will have built up natural immunity to it during the COVID-19 pandemic
- if you get flu and COVID-19 at the same time, research shows you’re more likely to be seriously ill
- getting vaccinated against flu and COVID-19 will provide protection for you and those around you for both these serious illnesses
If you’ve had COVID-19, it’s safe to have the flu vaccine. It will still be effective at helping to prevent flu.
Where Can I Find Information About Vaccine Supply
Information about vaccine supply is available here.
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Why Do Some People Not Feel Well Or Feel Like They Have Flu Symptoms After Getting A Flu Vaccine
While a flu vaccine cannot give you the flu, there may be times when you dont feel well after getting your flu vaccine. Heres why:
- You may get some mild and temporary side effects after your flu vaccine, such as soreness or redness where you got your shot, muscle aches, headache or a low fever. These common side effects usually begin soon after you get the vaccine and last 1-2 days. These reactions are a sign that your immune system is working and that your body is building protection against flu.
- You could become sick from other respiratory viruses that are spreading during flu season. A flu vaccine only protects you from the flu, not other illnesses like COVID-19 or the common cold.
- You could encounter flu viruses, which cause the flu, shortly before getting your flu vaccine or during the 2 weeks after getting the vaccine when your body is still building immunity. As a result, you could get the flu before the vaccine has the chance to protect you.
- You could experience flu-like symptoms, even after getting vaccinated, because you were exposed to a flu virus that is very different from the viruses that the vaccine is designed to protect against. There are many different flu viruses that spread and cause illness among people. However, even when the circulating flu viruses are not a perfect match to the strains in the flu vaccine, getting a flu vaccine should still help protect you against serious flu illness and its complications.
Ii4 Efficacy Effectiveness And Immunogenicity

Efficacy and effectiveness
Influenza vaccine has been shown in randomized controlled clinical trials to be efficacious in providing protection against influenza infection and illness. However, the effectiveness of the vaccine-that is, how it performs in settings that are more reflective of usual health care practice-can vary from season to season and by influenza vaccine strain type and subtype. Influenza vaccine effectiveness depends on how well the vaccine strains match with circulating influenza viruses, the type and subtype, as well as the health and age of the individual receiving the vaccine. Even when there is a less-than-ideal match or lower effectiveness against one strain, the possibility of lower VE should not preclude vaccination, particularly for people at high risk of influenza-related complications and hospitalization, since vaccinated individuals are still more likely to be protected compared to those who are unvaccinated.
Immunogenicity
Antibody response after vaccination depends on several factors, including the age of the recipient, prior and subsequent exposure to antigens, and the presence of immune compromising conditions. Protective levels of humoral antibodies, which correlate with protection against influenza infection, are generally achieved by 2 weeks after vaccination however, there may be some protection afforded before that time.
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Groups Who Should Especially Get The Vaccine
The flu shot can protect you against the flu. Because of this, it can reduce your chances of being infected with COVID-19 and the flu at the same time. This can lead to serious complications. You should especially receive the flu vaccine this season if youre:
- at high risk of severe COVID-19 related illness
- capable of spreading the flu to those at high risk of severe illness related to COVID-19
The flu vaccine is especially important for the following groups.
Can A Flu Vaccine Give Me The Flu
No. The way that flu vaccines are made, they cannot cause the flu. Flu shots are made from either flu viruses that have been inactivated OR with proteins from a flu virus. .
Nasal spray flu vaccine is made with weakened live flu viruses, and also cannot cause the flu. The weakened viruses are cold-adapted, which means they can only cause flu infection at the cooler temperatures found in your nose. These viruses cannot infect your lungs or other warmer areas of your body.
While some people may get mild side effects from a flu shot like a sore arm, a headache, muscle aches or a low fever, those side effects usually begin soon after the shot and only last 1 -2 days. These are actually signs that the vaccine is working and your body is building immunity.
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Who Should Not Receive A Flu Shot:
Most people should be vaccinated for influenza each year, But some people should not be vaccinated, or should not receive some types of influenza vaccines, depending upon things such as their age, health and whether they have certain allergies.
Information about who cannot get a flu vaccine and who should talk to their doctor before getting a flu vaccine is available at Who Should & Who Should NOT Get Vaccinated.
Iv Vaccine Preparations Authorized For Use In Canada: Additional Information
The following sections describe information on the efficacy and effectiveness, immunogenicity, and safety of influenza vaccines that are authorized for use in Canada by type: IIV and LAIV. Refer to Appendix A for a summary of the characteristics of specific influenza vaccine products available in Canada for the 2020-2021 season.
NACI acknowledges that evidence related to influenza vaccine performance, particularly with respect to vaccine efficacy and effectiveness, is constantly evolving with advances in research methodology and accumulation of data over many influenza seasons. Therefore, the evidence summarized in this section may not include the latest studies. However, in accordance with usual practice, NACI continues to closely monitor the emerging evidence on the efficacy and effectiveness, immunogenicity, and safety of influenza vaccines to update and to make recommendations when warranted.
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Where To Get The Flu Vaccine
You can have the NHS flu vaccine at:
- your GP surgery
- a pharmacy offering the service
- your midwifery service if you’re pregnant
- a hospital appointment
If you do not have your flu vaccine at your GP surgery, you do not have to tell the surgery. This will be done for you.
It’s important to go to your vaccination appointments unless you have symptoms of COVID-19.
Are There Delays In The Distribution Of Influenza Vaccine
Currently, influenza vaccine manufacturers are not reporting any expected delays in national flu vaccine supply or distribution this season.
Influenza vaccine production and distribution in the U.S. are primarily private sector endeavors. CDC encourages manufacturers and distributors to use a distribution strategy in which providers receive smaller shipments to allow as many providers as possible to begin vaccination activities early in the vaccination season. Ideally, the intervals between shipments are short so that each provider has a continuous supply and can continue vaccinating patients without interruption. While no important delays have been reported, in some places, robust demand for vaccine and supplies required to support flu vaccination efforts, like needles or syringes, may mean that some providers run out of vaccine or other supplies before their next shipment has arrived. An allocation system can initially limit the size of individual orders. However, as supplies become available in increasing numbers, supply is expected to catch up with demand. Additionally, because vaccine manufacturing has been extended to support the production of a record number of flu vaccine doses this year, providers are likely to receive more shipments throughout the season.
To make sure your provider has flu vaccine available, call ahead to confirm availability. There also may be other locations in your area that have vaccine available.
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What Are Some Key Reasons To Get A Flu Vaccine
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Every year, flu vaccination prevents illnesses, medical visits, hospitalizations, and deaths.
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Flu vaccination also is an important preventive tool for people with chronic health conditions. For example flu vaccination has been associated with lower rates of some cardiac events among in people with heart disease.
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Vaccinating pregnant women helps protect them from flu illness and hospitalization, and also has been shown to help protect the baby from flu infection for several months after birth, before the baby can be vaccinated.
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A 2017 study showed that flu vaccine can be life-saving in children.
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While some people who get vaccinated still get sick, flu vaccination has been shown in several studies to reduce severity of illness
Don’t Forget A Flu Vaccine This Season

Flu activity was kept low last season because of vaccination, social distancing, masking, school closures and limited travel. Now that pandemic restrictions are lifting, flu has a much higher chance of spreading. We can all do our part to prevent illness and hospitalizations caused by flu by getting vaccinated.
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What If I Am Allergic To Eggs
Some vaccines are grown using chicken eggs, so some people with egg allergies have avoided getting the shot. Those with mild or moderate egg allergies should still get the shot, Dr. Marcelin said. If you have a severe allergy, however, you should consult your doctor, who should supervise the vaccination. There is also an egg-free vaccine available.
If you are pregnant and allergic to eggs you should consult your doctor about the best vaccine for you.
Protect Yourself And Others From The Flu
Getting a flu shot is the best way to protect yourself and others from the flu. The flu shot is safe and available for free to all Nova Scotians 6 months of age and older. If you are 12 and older you can get a flu shot before, after, or at the same time as a COVID-19 vaccine. Children ages 5 to 11 need to wait 14 days between their flu shot and receiving their COVID-19 vaccine.
The flu vaccine is available from most family physicians, family practice nurses, nurse practitioners, pharmacists and walk-in clinics. You can contact your public health office if you’re unsure where to get the flu vaccine.
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Iii2 People Capable Of Transmitting Influenza To Those At High Risk Of Influenza
People who are potentially capable of transmitting influenza to those at high risk should receive annual vaccination, regardless of whether the high-risk individual has been vaccinated. Vaccination of HCWs decreases their own risk of illnessFootnote 52,Footnote 53, as well as the risk of death and other serious outcomes among the individuals for whom they provide careFootnote 54,Footnote 55,Footnote 56,Footnote 57. Vaccination of HCWs and residents of nursing homes is associated with decreased risk of ILI outbreaksFootnote 58.
People who are more likely to transmit influenza to those at high risk of influenza-related complications or hospitalization include:
- HCWs and other care providers in facilities and community settings who, through their activities, are capable of transmitting influenza to those at high risk and
- Contacts, both adults and children, of individuals at high risk, whether or not the individual at high risk has been vaccinated.
Health care workers and other care providers in facilities and community settings
Vaccination of health care workers and other care providers
Outbreak management in health care facilities
Contacts of individuals at high risk of influenza complications
How Serious Is The Threat Of A Twindemic
Medical experts dont know. Some hope that the measures taken against the coronavirus could also slow the spread of influenza.
Those precautions should be familiar by now: avoiding large groups, maintaining at least six feet of distance from others in public, washing your hands frequently, and wearing masks and other face coverings, especially indoors.
Dr. Schaffner said there have been some papers suggesting that very rigorous use of masks, social distancing and indeed the lockdown reduced the transmission of influenza in other countries.
But that may not be the case in the U.S., he warned. There are the real careful people who are being very attentive, he said, and then there are lots of people, unfortunately, in this country who are being rather careless and carefree.
This inconsistent behavior makes it hard to predict anything about the flu season.
But Dr. Ikediobi said that places with a good track record of following coronavirus precautions could have fewer cases of influenza. This is just a prediction.
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Administering Flu Vaccines During The Covid
CDC has released Interim Guidance for Immunization Services During the COVID-19 Pandemic. This guidance is intended to help immunization providers in a variety of clinical and alternative settings with the safe administration of vaccines during the COVID-19 pandemic. This guidance will be continually reassessed and updated based on the evolving epidemiology of COVID-19 in the United States. Healthcare providers who give vaccines should also consult guidance from state, local, tribal, and territorial health officials.
Information about coadministration of COVID-19 and other vaccines is available. .
What Should I Do If I Have Had A Serious Reaction To Seasonal Flu Vaccine
Tell your doctor what happened, the date and time it happened, and when you got the flu shot.
Ask your doctor, nurse, or health department to file a Vaccine Adverse Event Reporting System form, or call VAERS at 1-800-822-7967. Reports are welcome from all concerned individuals: patients, parents, health care providers, pharmacists and vaccine manufacturers.
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People 65 Years And Older Enhanced Quadrivalent Vaccine
Vaccination is particularly important for people in this age group as they are at high risk of complications from influenza and have the highest influenza-associated death rates each year.
The quadrivalent influenza vaccine Fluad Quad®is provided for people aged 65 years and older. It is an adjuvanted vaccine which is a standard dose flu vaccine with an added adjuvant to help create a stronger immune response to the vaccination. The 2022 vaccine contains the same components as the vaccine provided for other age groups but has the benefit of inducing a greater immune response in older people.
The enhanced quadrivalent influenza vaccine is the best form of protection against flu for older Queenslanders for the following reasons:
- Older people do not respond as well to standard influenza vaccine as the immune system response decreases with age.
- The enhanced vaccine is designed specifically to increase the immune system’s response to the vaccine, especially against the influenza A/H3N2 strain which is more common and severe in people aged 65 years and older.
Is The Flu Dangerous For Pregnant People

Yes. Flu can be very dangerous for pregnant people and their babies. The changes in immune, heart and lung function during pregnancy make you more likely to get seriously ill from the flu. If you get the flu while pregnant, it also increases your chance for complications, such as premature labor and delivery, and birth defects.
Getting a flu shot during your pregnancy helps protect both you and your baby. When you get vaccinated, your body makes antibodies that are passed to your baby, which helps protect them during their first few months of life, before they are able to start getting their own annual flu vaccinations.
Flu shots have safely been given to millions of people, including pregnant people, over many years. Numerous studies show that the flu vaccine is safe and effective for pregnant people and their babies.Pregnancy experts strongly recommend that all pregnant people get a flu shot. You can safely get the flu shot during any trimester.
Click here to view/download VYFs handout Flu Vaccination During Pregnancy.Learn more about flu and other vaccines recommended during pregnancy.
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