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.
How Does The Flu Vaccine Work
The flu jab does not protect 100%. It will decrease the chance of getting the flu. And if you do get the flu, the flu jab will usually make you less seriously ill.
When you get the flu vaccine your body will make antibodies against the flu. Antibodies are proteins in your blood that protect you from infections. The flu antibodies your body makes after a flu vaccine will lower your chance of getting the flu. You cannot get the flu from the flu jab.
The flu vaccine is very safe. The flu vaccine has been given to lots of people for many years. Sometimes after a flu vaccine you might get side effects. These are mild. Your arm where you got your vaccine might be painful, red or a little bit swollen. This will go away after one to two days. Side effects show that the vaccine is working, as the vaccine makes your immune system ready to fight a real flu infection.
After your flu vaccine it takes two or three weeks until you are protected. The flu vaccine does not protect you 100% from catching flu. After your flu vaccine you can sometimes still get the flu, but you will be less sick because of your flu vaccine.
Matching The Vaccine To The Virus
Vaccination is the best way to prevent contracting the flu.
Other public health measures, which have become the mainstay of preventing the spread of SARS-CoV-2, the new coronavirus, also feature heavily in flu prevention.
These include washing hands frequently, staying away from people who are sick, and covering coughs and sneezes.
But why do we need to get a flu vaccine every year? Influenza viruses mutate frequently, and the changes that these mutations introduce make it hard for our immune system to recognize and fight off new influenza strains and subtypes.
Scientists have to predict which influenza viruses are most likely to circulate during flu season to allow pharmaceutical companies to produce enough vaccine shots.
Each year the vaccine is different. Some years, it matches the circulating viruses better than in others.
In years with a good match, having a flu shot reduces the risk of falling ill with the flu by 4060% in the overall population.
A small research study from 2014 found that children who had received the flu shot during the 2010-11 and 2011-12 flu seasons were 74% less likely to need treatment in a pediatric intensive care unit than those who had not had the vaccine.
In a study of adults aged 18 and over in New Zealand, the researchers found that having a flu vaccine reduced the risk of admission to the intensive care unit by 82%.
However, according to the , having a flu shot can reduce the severity of a persons symptoms if they get the flu.
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Allergic Reactions To The Flu Vaccine
It’s very rare for anyone to have a serious allergic reaction to the flu vaccine. If this does happen, it usually happens within minutes.
The person who vaccinates you will be trained to deal with allergic reactions and treat them immediately.
Anyone can report a suspected side effect of a vaccine through the Yellow Card Scheme.
When Is The Best Time To Get A Flu Shot This Year Healthline
The Southern Hemisphere has been experiencing an unusual surge in flu cases early this season and experts say the same could happen in the United States later this year.
The Australian flu season usually spans from May to September, but this year the number of flu cases from mid-April exceeded the 5-year average.
The Australian experiences is suggestive that this could be a really bad flu season in the Northern Hemisphere as well, Dr. Dean Blumberg, the chief of pediatric infectious diseases at the University of California Davis Childrens Hospital, told Healthline.
Blumberg says the influenza season in the United States has been unusual since the COVID-19 pandemic began and this could have consequences for this years season.
We saw historically low rates of influenza during that 2021 flu season and relatively low rates during 21/22 in the U.S., and yet, we had lingering influenza cases that occurred in May and June and we were still seeing patients admitted to the hospital in May and June, treating them for influenza, which is highly unusual, he said.
In Australia so far this year, children younger than 5 and those aged between 5 and 19 had the highest rates of reported flu.
For the 2022/2023 flu season, the U.S. Centers for Disease Control and Prevention advises that every person over 6 months of age should be vaccinated against flu.
In this age group, these specific vaccines may produce a more effective immune response than the standard dose.
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When Should I Get Vaccinated
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You should get a flu vaccine before flu viruses begin spreading in your community since it takes about two weeks after vaccination for antibodies to develop in the body and provide protection against flu. Make plans to get vaccinated early in the fall, before flu season begins. CDC recommends that people get a flu vaccine by the end of October. However, getting vaccinated early is likely to be associated with reduced protection against flu infection later in the flu season, particularly among older adults. Vaccination should continue to be offered throughout the flu season, even into January or later. Children who need two doses of vaccine to be protected should start the vaccination process sooner of vaccine to be protected should start the vaccination process sooner because the two doses must be given at least four weeks apart.
Why Do I Need To Get Vaccinated Every Year
Youve probably noticed by now that we encourage our patients to get vaccinated each year. Why does this particular vaccine need to be administered again, even if you got a flu shot last year? Its because new strains of the virus are constantly appearing and evolving, so the vaccine must change along with them.
Located around the world are influenza surveillance centers that annually monitor the most common strains, collecting data and identifying new and evolving strains. Once the information has been collected, the World Health Organization selects the three strains most likely to circulate during the following flu season. This decision is typically made in February, allowing the development of a new vaccine to begin around midsummer.
Because the three strains change each year, the vaccines are formulated separately before theyre combined into the final product, the trivalent vaccine. While its usually fairly accurate, there have been instances, such as the infamous H1N1 outbreak in 2009, that required the addition of a second, separate vaccination.
In addition to the constantly evolving strains of the flu virus, your bodys immune response changes over time. Taken together, those two factors essentially render the previous years vaccinations useless against new strains. This is why its so important to get yourself vaccinated each and every year, even if you got the vaccine last year!
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When The Flu Vaccine Starts Working
Once you receive your flu shot, it takes 2 weeks for your body to develop antibodies that provide protection.
Its important to remember that during this period, youre still vulnerable to becoming ill with the flu.
During that time, you should be extra careful to:
- practice good hygiene
- avoid touching your nose or mouth whenever possible
- avoid crowds if flu is circulating in your community
These precautions are exponentially more important while COVID-19 is still a factor. You can develop the flu along with other respiratory infections, so protecting yourself and others is important.
When Should I Get The Flu Vaccine
Make plans to get vaccinated early in the fall before flu season begins. You should get a flu vaccine before flu viruses begin spreading in your community. It takes about two weeks after vaccination for antibodies to develop in the body and provide protection against the flu. The Centers for Disease Control and Prevention recommends that people get a flu vaccine by the end of October. Getting vaccinated later, however, can still be beneficial.
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How Effective Is The Flu Vaccine
The flu vaccine gives the best protection against flu.
Flu vaccines help protect against the main types of flu viruses, although there’s still a chance you might get flu.
If you do get flu after vaccination, it’s likely to be milder and not last as long.
Having the flu vaccine will also reduce the chance of you spreading flu to other people who may be more at risk of serious problems from flu.
It can take 10 to 14 days for the flu vaccine to work.
Be A Flu Fighter By Getting Your Annual Flu Shot
There are a lot of reasons to get a flu shot. Its fast. Its easy. Its almost always free. But maybe one of the most important reasons is that it can significantly reduce your risk of getting the flu and passing it to others. And this helps you, your family and community stay healthy, happy and productive.
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How The Flu Vaccine Works
Development of the seasonal flu vaccine actually begins many months ahead of flu season. The viruses used in the vaccine are based on extensive research and surveillance into which strains will be most common during the upcoming season.
Seasonal flu vaccines protect against two types of influenza viruses: influenza A and influenza B. They can also be either trivalent or quadrivalent.
The trivalent vaccine protects against three flu viruses: two influenza A viruses and an influenza B virus.
The quadrivalent vaccine protects against the same three viruses as the trivalent vaccine, but it also includes an additional influenza B virus.
Who Should Get A Flu Vaccine This Season
Everyone 6 months and older should get a flu vaccine every season with rare exceptions. Vaccination is particularly important for people who are at higher risk of serious complications from influenza. A full listing of people at Higher Risk of Developing Flu-Related Complications is available.
Flu vaccination has important benefits. It can reduce flu illnesses, doctors visits, and missed work and school due to flu, as well as prevent flu-related hospitalizations and deaths.
Different flu vaccines are approved for use in different groups of people.
- There are flu shots approved for use in children as young as 6 months old and flu shots approved for use in adults 65 years and older.
- Flu shots also are recommended for pregnant people and people with certain chronic health conditions.
- The nasal spray flu vaccine is approved for use in non-pregnant people who are 2 years through 49 years of age. People who are pregnant and people with certain medical conditions should not receive the nasal spray flu vaccine.
There are many vaccine options to choose from. CDC does not recommend any one flu vaccine over another. 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 flu vaccine to get, talk to your doctor or other health care professional. More information is available at Who Should Get Vaccinated.
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Shortage Of Iv Fluids Amid Flu Outbreak
The prevention of severe and fatal infection caused by influenza was observed mainly in patients who were vaccinated in both the current and previous seasons, Dr. Itziar Casado and Dr. Jesús Castilla of the Institute for Public Health in Pamplona, Spain, wrote in the Canadian Medical Association Journal.
“Repeated vaccination for influenza was highly effective in preventing severe and fatal infection caused by influenza in older adults,” they added.
This makes sense to David Topham, a microbiologist and immunologist at the University of Rochester Medical Center, who was not involved in the research.
We probably only get exposed to influenza, the virus, every three to five years on average, Topham told NBC News.
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Thats plenty of time for your immunity to wane. Getting the vaccine every year boosts your immunity.
And repeated vaccination may cause broader immunity, both Topham and the researchers said. Vaccines stimulate both the production of antibodies and cells called T-cells to fight germs. Repeated vaccination might more effectively boost the action of T-cells.
Its a reassuring finding. A couple of small studies had suggested that getting the flu vaccine every year might increase some peoples risk of catching flu, even though it was hard to explain why that might happen. Topham said he did not think the evidence shows repeated vaccines are harmful.
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Are Flu Vaccines 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.
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How Flu Vaccine Virus Strains Are Selected
Every year, in late February or early March, before that years flu season ends, the FDA, the World Health Organization , the CDC, and other public health experts collaborate on collecting and reviewing data from around the world to identify the flu viruses likely to cause the most illnesses during the next flu season.
Following that process, the FDA convenes its vaccines advisory committee, consisting of outside experts, to discuss the WHO recommendations and to consider which flu viruses are expected to circulate in the U.S. The committee also reviews data about which flu viruses have caused illnesses in the past year, how the viruses are changing, and disease trends for the U.S. The FDA takes that information into account before it selects the virus strains for FDA-licensed manufacturers to include in their vaccines for use in the U.S.
The closer the match between the virus strains chosen for the vaccine and the circulating strains causing disease during flu season, the better the protection that the flu vaccine provides. Although the vaccine and viruses may not be an exact match in some years, that does not mean the vaccine is not benefiting people. Available data show that the vaccine can reduce the severity of illness in people who get vaccinated but still get sick.
Dispelling Misinformation About The Flu Vaccine Sickness Treatment And Recovery
If you’ve ever had the flu, you know how sick you can be. Chances are good that some of the advice friends and family gave you about avoiding or dealing with the flu was wrong. There seems to be no shortage of misinformation and bad advice when it comes to dealing with the flu and the flu shot.
Here are 10 common myths about the flu.
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