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.
What Are The Possible Side Effects Of The Flu Vaccine
Both types of vaccine can cause mild side effects.
- The flu shot usually is given as an injection in the upper arm or thigh . It contains killed flu virus and can’t cause someone to get the flu. But it can cause soreness, redness, or swelling at the injection site. Rarely, it might cause a low fever or body aches.
- The nasal spray flu vaccine contains weakened live flu viruses. So it may cause mild symptoms, such as a runny nose, wheezing, sore throat, vomiting, or tiredness. Like the shot, it can sometimes cause a low fever or body aches.
Sometimes, people faint after getting a shot, especially teens. It helps to sit or lie down for 15 minutes right after a shot to prevent this.
If your child has any side effects, talk to your doctor about giving either acetaminophen or ibuprofen and to find out the right dose.
A warm, damp cloth or a heating pad on the injection site may help ease soreness, as can moving or using the arm.
Very rarely, the flu vaccine can cause a serious allergic reaction.
Who Should Receive The Flu Vaccine
The CDC recommends that every individual over 6 months of age receive the seasonal flu vaccine. While everyone should get a vaccination, it is particularly important for some groups. Vaccination is especially important for people who are at high risk of developing serious complications if they get the flu, such as those with asthma, diabetes, and chronic lung disease as well as pregnant women and those over 65 years of age. It is also important for caregivers to get vaccinations, in addition to those who live with people in these risk groups.
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What About People Who Get A Seasonal Flu Vaccine And Still Get Sick With Flu Symptoms
There are several reasons why someone might get flu symptoms, even after they have been vaccinated against flu.
Is It Ever Too Late
![Concerns about access to flu shots during pandemic [Video] Concerns about access to flu shots during pandemic [Video]](https://www.flutalk.net/wp-content/uploads/concerns-about-access-to-flu-shots-during-pandemic-video-scaled.jpeg)
Flu shots are typically given in the early fall through March or April. CDC recommends getting a flu shot by the end of October. However, as long as the flu virus is making people sick in your community, it’s worth getting vaccinated against it. It won’t provide full protection immediately, but it could still prevent you from getting sick.
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How To Book Your Appointment
If you’re eligible for a free flu vaccine, you can book an appointment at your GP surgery or a pharmacy that offers it on the NHS.
You may also get an invitation to get the vaccine, but you do not have to wait for this before booking an appointment.
Everyone who is eligible for the free flu vaccine will be able to get it.
GP surgeries and pharmacies get the flu vaccine in batches. If you cannot get an appointment straight away, ask if you can book an appointment for when more vaccines are available.
If you have an appointment for a COVID-19 booster vaccine at a GP surgery or pharmacy, you may also be offered a flu vaccine at the same time.
Do not delay booking your flu vaccine appointment so that you can get both vaccines together. Only some people will be offered both vaccines at the same time.
Flu Vaccine Ingredients: The Strains
Every year, vaccine developers take virus samples from labs across the world and mix and match them. This years vaccine relies on four viruses this is called a quadrivalent vaccine. The four viruses in the vaccine are somewhat different for the three different types of flu vaccines, which are egg-based , recombinant, and egg-free.
Those viruses are
Apdm09
First, lets break down the terminology: A refers to the type of influenza that infects birds, humans, pigs, horses, seals, and dogs H#N# refers to the different proteins found in the outer shell of the virus pdm is short for pandemic and 09 is the year of said pandemic .
This years Apdm09 component is different for flu vaccines that are egg-based compared to those that are cell-based and recombinant-based. For egg-based vaccines, the component remained the same as last year: an A/Victoria/2570/2019pdm09-like virus. That refers to a flu strain akin to the one seen in the 2009 pandemic that was created in 2019 in a lab in Victoria.
For cell-based and recombinant vaccines, the component remained the same as last year: an A/Wisconsin/588/2019 pdm09-like virus.
The second component is a variant of the 2009 H1N1 swine flu. H3N2 was first found in pigs in 2010, then in humans in 2011. The biggest human outbreak was in 2012 with some 309 reported cases.
Influenza B
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Flu And Pneumonia Shots
Having the flu can be dangerous for anyone. But it is extra risky for people with diabetes or other chronic health problems. Having diabetes means having more instances of high blood glucose than a person without diabetes. High blood glucose hinders your white blood cells ability to fight infections.
Beyond people living with diabetes, flu is also extra risky for people with heart disease, smokers and those with chronic lung disease, people who have an impaired immune system , very young children, and people living in very close quarters, such as college dorms, military barracks, or nursing homes.
Can You Get Covid
According to the CDC, “While it’s not possible to say with certainty what will happen in the fall and winter , CDC believes it’s likely that flu viruses and the virus that causes COVID-19 will both be spreading. In this context, getting a flu vaccine will be more important than ever.” There is no evidence to suggest that it is not possible to have both diseases at the same time.
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Evergreen Flu Vaccine Ingredients: The Preservatives And Additives
Beyond the three to four viral components, a number of additives and preservatives are required to make vaccines effective and to keep them from going bad. These ingredients, sometimes covered as trade secrets by drug companies in less public drugs, have led to many a conspiracy theory that anti-vaxxers would have you latch onto. Its really much more boring than that.
Here are some of the ingredients you will find in the 2022-2023 flu vaccine and why theyre there.
The Ingredient: Aluminum Salts
Use: Boosts bodys response to the vaccine
The Ingredient: Sugar or gelatin
In: Most vaccines
In: Few flu vaccines only multi-dose vials
Use: Preservative
The CDC says: Thimerosal has a different form of mercury than the kind that causes mercury poisoning . Its safe to use ethylmercury in vaccines because its processed differently in the body and its less likely to build up in the body and because its used in tiny amounts. Even so, most vaccines do not have any thimerosal in them.
The Ingredient: Egg proteins
In: Some vaccines
Use: Growing the vaccine
The CDC says: Because influenza and yellow fever vaccines are both made in eggs, egg proteins are present in the final products. However, there are two new flu vaccines now available for people with egg allergies.
Is It Safe To Have A Coronavirus Vaccine If You Already Had A Flu Vaccine
There is no coronavirus vaccine currently available, but vaccine developers are working to ensure development of a vaccine that is safe for everyone, including those who have had flu shots. Currently in the absence of a coronavirus vaccine, it is especially important for the 2020-21 flu season to receive a flu shot for its overall health benefits.
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Managing Side Effects After Immunisation
Common side effects following immunisation are usually mild and temporary . Specific treatment is not usually required. There are several treatment options that can reduce the side effects of the vaccine including:
- Drinking extra fluids and not overdressing if there is a fever.
- Although routine use of paracetamol after vaccination is not recommended, if pain and fever are present, paracetamol can be given check the label for the correct dose or speak with your pharmacist .
Who Shouldn’t Get A Flu Shot

The flu vaccine is not right for everyone. You should not get a flu shot if you have:
- Fever or moderate to severe illness at the time of vaccination
- History of previous severe or life-threatening allergic reaction to a flu shot
Infants under 6 months old should also not receive the flu shot. Additionally, if you have a history of Guillain-Barré syndrome after previous flu vaccinations, talk to your healthcare provider before getting a flu shot again.
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What Flu Vaccines Are Available Via Jet Injector This Season
One flu vaccine, AFLURIA Quadrivalent®, is approved for use with a jet injector this season. AFLURIA Quadrivalent® flu vaccine provides protection against an influenza A virus, and influenza A virus and two influenza B viruses. For more information, see What You Should Know for the 2022-2023 Season.
How To Administer A Flu Shot
This article was medically reviewed by Shari Forschen, NP, MA. Shari Forschen is a Registered Nurse at Sanford Health in North Dakota. She received her Family Nurse Practitioner Master’s from the University of North Dakota and has been a nurse since 2003.There are 17 references cited in this article, which can be found at the bottom of the page.wikiHow marks an article as reader-approved once it receives enough positive feedback. In this case, several readers have written to tell us that this article was helpful to them, earning it our reader-approved status. This article has been viewed 369,703 times.
Experts say that an annual flu shot is your best bet for preventing the flu, but it’s not 100% effective.XTrustworthy SourceMayo ClinicEducational website from one of the world’s leading hospitalsGo to source Typically, the annual flu shot will protect you against 3 or 4 strains of the virus that are expected to be prevalent that flu season. Research suggests that flu shots are usually given in the upper arm, and you may get a specific type recommended for your age group.XTrustworthy SourceCenters for Disease Control and PreventionMain public health institute for the US, run by the Dept. of Health and Human ServicesGo to source Fortunately, flu shots are fairly easy to administer.
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What Are The Types Of Flu Vaccines
Two types of flu vaccine are available for the 20212022 flu season:
- the flu shot, which is injected with a needle
- the nasal spray, a mist that gets sprayed into the nostrils
Both protect against the four types of influenza virus that are causing disease this season.
In the past, the nasal spray vaccine wasn’t recommended for kids because it didn’t seem to work well enough. The newer version appears to work as well as the shot. So either vaccine can be given this year, depending on the child’s age and general health.
The nasal spray is only for healthy people ages 249. People with weak immune systems or some health conditions and pregnant women should not get the nasal spray vaccine. It should also be avoided in kids who take aspirin regularly, who have a cochlear implant, or who have recently taken antiviral medicine for the flu.
Why Do I Need A Flu Vaccine Every Year
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A flu vaccine is needed every season for two reasons. First, a persons immune protection from vaccination declines over time, so an annual vaccine is needed for optimal protection. Second, because flu viruses are constantly changing, flu vaccines may be updated from one season to the next to protect against the viruses that research suggests may be most common during the upcoming flu season. For the best protection, everyone 6 months and older should get vaccinated annually.
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Who Should Not Get The Flu Shot
Very few children should NOT get a flu shot:
- Babies under 6 months of age. Although the vaccine is not harmful to babies less than 6 months old, it does not work.
- If your child has a serious allergy to thimerosal , a thimerosal-free vaccine should be given.
The influenza vaccine is safe for individuals with an egg allergy.
How Safe Is The Flu Vaccine
The influenza vaccine is very safe. It cannot cause the flu. Side effects are usually mild and can include:
- mild soreness where the needle went into the arm for 1 to 2 days.
- a mild fever or aches for the first day or 2 after immunization.
Do not give your child ibuprofen or acetaminophen before or around the time of vaccination as it does not prevent the pain of injection and it could have an impact on how well the vaccine works. These medications can be used to treat fever, pain, or other bothersome side effects if they develop after vaccination.
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What Protection Does A Flu Vaccine Provide If I Do Get Sick With Flu
Some people who get vaccinated may still get sick. However, flu vaccination has been shown in several studies to reduce severity of illness in people who get vaccinated but still get sick:
- A 2017 study showed that flu vaccination reduced deaths, intensive care unit admissions, ICU length of stay, and overall duration of hospitalization among hospitalized flu patients.
- Another study in 2018 showed that a vaccinated adult who was hospitalized with flu was 59% less likely to be admitted to an intensive care unit than someone who had not been vaccinated. Among adults in the ICU with flu, vaccinated patients on average spent 4 fewer days in the hospital than those who were not vaccinated.
In addition, its important to remember that flu vaccine protects against three or four different viruses and multiple viruses usually circulate during any one season. For these reasons, CDC continues to recommend flu vaccination for everyone 6 months and older even if vaccine effectiveness against one or more viruses is reduced.
When To Get The Influenza Vaccine

Yearly vaccination before the onset of each flu season is recommended. In most parts of Australia, flu season occurs from June to September, with the flu vaccine typically available from April.
Recent evidence suggests optimal protection against the flu occurs within the first 3-4 months following vaccination. It is important to note that, while the influenza virus continues to circulate, it is never too late to vaccinate.
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Are There Any Flu Vaccines Without Needles
Yes, there are two flu vaccines available without needles: the Afluria Quadrivalent given via the PharmaJet Stratis Needle-Free Injector and the intranasal FluMist vaccine.
Afluria Quadrivalent can be given via a needle-free jet injector or with a needle.
- If you are 18 through 64 years of age and are eligible for a flu vaccine, you can request needle-free Afluria. First check with your doctor, clinic, or pharmacy to be sure they have the jet injector. Call your insurance to be sure it is covered, too.
- It’s not 100% pain-free, but the jet injector creates a narrow stream of fluid that goes through the skin, without a needle, given in one-tenth of one second.
- Children 6 months through 17 years and adults 65 and older can receive Afluria Quadrivalent only by a needle and syringe.
FluMist is an intranasal flu vaccine spray.
- FluMist Quadrivalent is a needle-free option that is used in certain populations between the ages of 2 to 49 years to help prevent influenza. It is a liquid vaccine that is sprayed into the nose.
- Not everyone can use FluMist. Children under 2 years of age cannot use it due to an increased risk of wheezing. Tell your healthcare provider if you are currently wheezing, or have a history of wheezing.
- In addition, anyone with a severe allergy to eggs, anyone who has had a life-threatening allergic reaction to any flu vaccine, and children 2 through 17 years old who take aspirin or medicines containing aspirin cannot use FluMist.
Reaction At The Injection Site
The most common side effect of the flu shot is a reaction at the injection site, which is typically on the upper arm. After the shot is given, you may have soreness, redness, warmth, and in some cases, slight swelling. These effects usually last less than two days.
To help reduce discomfort, try taking some ibuprofen before getting your shot.
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