What Is Herd Immunity
Another term for herd immunity is community immunity. When enough people in a community are vaccinated against a particular virus, the virus won’t be able to easily spread. Some people can’t get vaccinated, and others are vaccinated but don’t have strong immune responses. These people are especially vulnerable and rely on herd immunity for protection against diseases. Every time you get vaccinated you are protecting yourself, your family and your community.
Comprehensive Solutions For Immunizations Testing And Treatment
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Flu Shot Timing: What’s Optimal
Aug. 30, 2021 — Amid fresh national recommendations for COVID booster shots to ramp up waning immunity, new research examining the durability of flu vaccination indicates significantly dwindling protection just months after inoculation.
Maximum influenza vaccine efficacy in adults occurred shortly after vaccination, followed by an average decline of 8% to 9% each month and an even swifter drop among older adults.
Even a 1- or 2-month delay in annual flu vaccination could improve vaccine effectiveness by 10% to 20%, according to the study, published August 15 in Clinical Infectious Diseases.
Analyzing vaccine timing relative to influenza-associated hospitalizations among more than 5500 adults, the findings are broadly consistent with both early and more recent studies, says study author Jill Ferdinands, PhD, an epidemiologist in the Influenza Division of the National Center for Immunization and Respiratory Diseases at the CDC.
“These findings are not surprising,” Ferdinands tells Medscape Medical News. “In the very first successful trial of inactivated influenza vaccine in 1943, the study’s authors observed that antibodies to influenza declined by about one third within 4 to 5 months after vaccination.”
But “a better understanding of waning immunity, like the information gained by this study, could help further optimize the recommendation,” she says.
He says the COVID pandemic might prove to “actually be a shot in the arm for influenza vaccine research.”
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When Is The Best Time To Get Vaccinated
The best time to get vaccinated is whenever you can though October seems to be a pretty good sweet spot for staying protected through the end of flu season, earlier is totally OK, too, said Temple-Wood.
Definitely dont wait if you have the opportunity! she said. Theres no such thing as too late, either. If youre being offered the flu shot, its because theres still flu hanging around.
When Should You Get Your Flu Shot

Its generally recommended that people get a flu vaccine by the end of October, according to the CDC. This is especially important because of the ongoing spread of COVID-19. The flu season peaks often in February and can last until May, so you can still get the flu vaccine later. No matter when you get your flu shot, it will still be valuable to help protect you for the rest of the flu season. Talk to your provider about the best time to get your flu shot. Remember to ask about other vaccines you might need to protect yourself this year too.
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Factors In Flu Shot Effectiveness
Influenza viruses are constantly changing and evolving rapidly. Circulating influenza viruses can mutate from one season to the next.
Researchers need to select the specific influenza viruses to include in the vaccine many months before flu season begins. This means whats in the vaccine may not always match whats actually circulating during flu season. This can decrease the effectiveness of the seasonal flu vaccine.
Age can also play a role in vaccine efficacy because your immune system tends to become weaker as you age. The Food and Drug Administration has approved a high-dose flu vaccine for people 65 and older.
The higher dose is aimed at providing a better immune response and therefore better protection within this age group. for those over 65 with the high-dose vaccine.
The CDC also recommends that some children between the ages of 6 months and 8 years receive two doses of the influenza vaccine during the first season in which theyre vaccinated in order to have sufficient protection.
Its still possible to get the flu after being vaccinated, but research has shown that the illness may be less severe and that people who receive a flu shot may be less likely to be admitted to the hospital if they get the flu.
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.
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How Do I Get Vaccinated If I Dont Have Health Insurance
Without insurance, the out-of-pocket cost will typically be around $40 for the regular dose, with an added cost for a senior dose, said Shultz.
She recommended checking with services like Blink Health or GoodRx to see if any discounts are available in your area, and VaccineFinder can help you locate pharmacies near you.
There are also a number of options that provide free or discounted shots. Some schools and workplaces will hold events offering a flu shot to all members of their communities. Most county health departments also offer free or significantly discounted vaccines for people without insurance or could provide you with more information about where to go in your community, said Shultz.
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.
- Someone can get sick with another respiratory virus besides flu such as rhinoviruses or SARS-CoV-2 . Other respiratory viruses can cause symptoms similar to flu, and they can also spread and cause illness during flu season. Flu vaccines only protect against flu and its complications, not other illnesses.
- Someone can be exposed to flu viruses shortly before getting vaccinated or during the two-week period after vaccination that it takes the body to develop immune protection. This exposure may result in a person becoming sick with flu before protection from vaccination takes effect.
- Flu vaccines vary in how well they work, and someone can get vaccinated but still get sick with flu. There are many different flu viruses that spread and cause illness among people, so this can happen if someone is exposed to a flu virus that is very different from the viruses in the flu vaccine. The ability of a flu vaccine to protect a person depends partially on the similarity or match between the vaccine viruses chosen to make vaccine and those spreading and causing illness. Even when that happens though, flu vaccination can still reduce severity of illness.
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The Flu Shot: What You Need To Know
Getting a flu shot each year is the best way to protect against the flu, and during COVID-19, a flu shot may be even more important.
Receiving a flu vaccine reduces the chance of flu-related doctor visits and hospitalizations, which can free up healthcare resources for others and protect vulnerable populations during the pandemic.
Can You Get The Flu From The Flu Vaccine
Temple-Wood explained that the flu shot is an inactivated or killed virus vaccine, which means you cant get sick from the shot.
When you get the shot, your immune system makes antibodies against the dead viruses, and these antibodies protect you from being infected by the live virus, she said.
Jessica Malaty Rivera, MS, infectious disease researcher and science communication lead at the COVID Tracking Project agreed: No, you cannot get the flu from the flu vaccine.
Even the nasal spray flu vaccine which contains live, but weakened, virus will not cause the flu.
Rivera added, For those who are vaccinated against flu and still get the flu during flu season, symptoms are often milder as a result of vaccination.
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What Are Other Ways I Can Protect Against The Flu
In addition to your yearly flu vaccine, there are a few other things you can do to protect your family and yourself from the flu. There are daily precautions you can take such as limiting contact with sick people as much as possible and washing your hands with soap and water often. If you have received a prescription for flu antiviral medications, it’s important to take them as directed by your healthcare provider.
But remember, the No. 1 way to protect yourself and your family against the flu virus is to get vaccinated every year.
Clinically reviewed and updated June 2021.
You Have An Unrelated Case Of The Flu

It takes about two weeks for the flu vaccine to start working. If you’re exposed to an influenza virus during this period, you can still get sick with the flu. Also, you may have been exposed to a flu virus shortly before getting your shot.
Lastly, the strains of flu included in the flu shot vary from year to year. Unfortunately, it is particularly prone to change, with new strains appearing often. Scientists work to target the strains that will be the most prevalent that season so that the vaccination can be tailored accordingly. Despite their best efforts, they may sometimes get it wrong.
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What Is A Flu Vaccine
Influenza vaccines are vaccines that protect against the four influenza viruses that research indicates will be most common during the upcoming season. Most flu vaccines are flu shots given with a needle, usually in the arm, but there also is a nasal spray flu vaccine.
Local Health Departments Community Centers Or Religious Sites
Many county health departments offer free flu shots during flu seasonwith or without insurance. Contact your county’s health department to see if you can benefit from this service. Even if you don’t have health insurance , you may be able to get the jab without cost through local churches and synagogues, free clinics, and community centers.
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Why Is My Arm Sore After I Get My Flu Shot
Temple-Wood explained that your arm gets sore after a flu shot for a couple of reasons.
The first one is that you got stabbed a little bit and any kind of poke hurts. The second reason is that your immune system is busy mustering that response to the killed viruses in the vaccine. This involves sending white blood cells to the area and increasing blood flow, which causes swelling as well, she said.
Temple-Wood added that the best way to reduce or prevent pain or swelling at the injection site is to relax your arm as much as possible while youre getting your flu shot.
It also helps to move your arm more afterward to get lymphatic flow moving. You can also use heat or cold packs, and over-the-counter pain medications if the pain is severe and your doctor says its OK.
How Do I Get A Flu Vaccine At Target
To get a Target flu shot, visit any location with a CVS Pharmacy or MinuteClinic. You can either walk-in or make an appointment at the CVS website, on the CVS app, or by texting FLU to 287898. You can also fill out a consent form online.
Your confirmation email will contain a link you can use to check in once you get to the store. Most insurance plans, including Medicare Part B, cover the cost of flu vaccines.
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Is There Mercury In The Flu Shot
Vials of vaccine that contain more than one dose contain thimerosal, which is a mercury-based preservative. These multi-dose vials have a preservative because every time a needle enters the vial there is a risk of introducing bacteria or fungi, which could be dangerous. Thimerosal protects the vaccines from contamination. Our bodies remove thimerosal quickly and easily, so it does not stay or build up in our system. Flu vaccines available as single-dose, pre-filled syringes and nasal spray formulations of the flu vaccine do not contain thimerosal.
Flu Symptoms & Complications
Influenza can cause mild to severe illness, and at times can lead to death. Flu symptoms usually come on suddenly. People who have flu often feel some or all of these symptoms:
- fever* or feeling feverish/chills
- some people may have vomiting and diarrhea, though this is more common in children than adults.
*Its important to note that not everyone with flu will have a fever.
This video includes common signs and symptoms of flu.
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Can You Get The Flu From A Flu Shot
Some people worry about getting a flu shot because they fear they will get sick from the vaccine. Rest assured, it is not possible to get influenza from the flu shot. It does not contain intact viruses that can cause infection. It is possible that you might not feel well after you get a flu shot, but that may be for any of several other reasons.
When Should I Get The Flu Shot

The flu season varies from year to year, but it has been known to start as early as October, peak in the winter months between December and February, and then may continue as late as May. The CDC recommends getting the flu vaccine early in the fall before the flu season begins, ideally no later than the end of October. It takes about two weeks after vaccination for your body to build up the antibodies against the flu. It’s better late than never, though. Even if you don’t get the flu vaccine until January or later, you can still benefit from it.
It’s important to get the flu vaccine every year because both you and the flu virus change. The antibodies that you create to build immunity to the flu will decrease with time, so you need a new vaccine to renew your supply of antibodies. The flu viruses are also constantly changing, which is why there is a new formulation every year.
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People At Higher Risk From Flu
Anyone can get sick with flu, even healthy people, and serious problems related to flu can happen to anyone at any age, but some people are at higher risk of developing serious flu-related complications if they get sick. This includes people 65 years and older, people of any age with certain chronic medical conditions , pregnant people and children younger than 5 years, but especially those younger than 2 years old.
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 There More Than One Type Of Flu Shot Available
Yes. There are different flu vaccine manufacturers and multiple flu vaccines that are licensed and recommended for use in the United States.
For people younger than 65 years, CDC does not preferentially recommend any licensed, age-appropriate influenza vaccine over another during the 2022-2023 flu season. Options for this age group include inactivated influenza vaccine , recombinant influenza vaccine , or live attenuated influenza vaccine , with no preference for any flu vaccine over another.
New for this season: For people 65 years and older, there are three flu vaccines that are preferentially recommended overstandard-dose, unadjuvanted flu vaccines. These are Fluzone High-DoseQuadrivalent vaccine, Flublok Quadrivalent recombinantflu vaccine and Fluad Quadrivalent adjuvanted flu vaccine. More information is available at Flu & People 65 Years and Older.
All flu vaccines for the 2022-2023 season are quadrivalent vaccines, designed to protect against four different flu viruses, including two influenza A viruses and two influenza B viruses. Different vaccines are licensed for use in different age groups, and some vaccines are not recommended for some groups of people.
Available flu vaccines include: