Key TakeawaysMost people only need one annual influenza vaccine to be protected for the entire season.Flu shots don’t really have boosters like other vaccines do, but there are some cases where a person might need a second shot in the same flu season. For example, children ages 6 months to 8 years who are getting flu shots for the first time. They will need two doses of flu vaccine that are spaced four weeks apart.Experts are predicting a more severe cold and flu season this year, which is why getting your flu shot as soon as possible is important.

Key Takeaways

Most people only need one annual influenza vaccine to be protected for the entire season.Flu shots don’t really have boosters like other vaccines do, but there are some cases where a person might need a second shot in the same flu season. For example, children ages 6 months to 8 years who are getting flu shots for the first time. They will need two doses of flu vaccine that are spaced four weeks apart.Experts are predicting a more severe cold and flu season this year, which is why getting your flu shot as soon as possible is important.

With a longer andmore severe cold and flu season expected this year, many are wondering if one dose of theinfluenza vaccinewill be enough to ward off severe illness and dangerous respiratory complications.

With a lot of talk about extra vaccine doses and booster shots for COVID-19, you might wonder if getting two flu shots would offer more protection—or if it’s even possible to get more than one flu shot in the same season.

Just one flu shot a year is recommended (and enough) for most people, but there are exceptions—for example,kids who are getting a flu shot for the first time.

According to Mathew, “everyone else only needs to get a single influenza vaccine for the season.”

Can the Flu Shot Give You the Flu?

How Well Does One Flu Shot Work?

Each February, the United States works with the World Health Organization (WHO) to determine the formulation of the flu vaccine for the upcoming influenza season. The goal is to closely match the same viruses that are currently circulating and causing illness.

All U.S. flu vaccines protect against typeA and B viruses. This includes a flu A(H1) virus, a flu A(H3) virus, a flu B/Yamagata lineage virus, and a flu B/Victoria lineage virus. Flu vaccine components are determined based on current international data, including:

How Well Do Flu Shots Work?

While kids benefit from two flu shots, there is not enough evidence to show that it would be helpful for any other groups to get a second dose.

Some studies in adults with compromised immune systems (like organ transplant recipients) have looked at whether getting a second flu shot might be helpful, but more research is needed before the recommendation would be changed.

Currently, theCenters for Disease Control and Prevention (CDC) statesthat for adults, “studies have not shown a benefit from getting more than one dose of vaccine during the same influenza season, even among elderly persons with weakened immune systems.”

What If I Get Two Flu Shots By Mistake?

How Long Does Flu Shot Protection Last?

According to experts, flu vaccine immunity wanes over time but typically provides protection for five to six months. However, this timeframe depends on different factors like a person’s age and the strain of flu virus that’s going around.

Buddy Creech, MDWe know that vaccine effectiveness wanes through the season, with some estimating an approximate 5% loss each month following vaccination.

Buddy Creech, MD

We know that vaccine effectiveness wanes through the season, with some estimating an approximate 5% loss each month following vaccination.

When to Get a Flu Shot for the 2022-2023 Season

“The length of the influenza season is, indeed, relevant to our strategy for vaccination,”Buddy Creech, MD, MPH, a professor and chair in the Department of Pediatrics at the Vanderbilt University Medical Center and the director of the Vanderbilt Vaccine Research Program, told Verywell. “We know that vaccine effectiveness wanes through the season, with some estimating an approximate 5% loss each month following vaccination.”

“[I] think it’s fair to say that the longer we go after vaccination, the less immunity we have.”

Reasons You Might Want to Get a Flu Shot EarlySome people may want to get their yearly flu shot a little sooner. For example:Travelers who missed vaccination in the previous winter or fallChildren younger than age 9 who needed two doses of the flu vaccine but did not get their second dose early in the seasonPeople who may not be able to get vaccinated later in the seasonPeople in thethird trimester of pregnancy

Reasons You Might Want to Get a Flu Shot Early

Some people may want to get their yearly flu shot a little sooner. For example:Travelers who missed vaccination in the previous winter or fallChildren younger than age 9 who needed two doses of the flu vaccine but did not get their second dose early in the seasonPeople who may not be able to get vaccinated later in the seasonPeople in thethird trimester of pregnancy

Some people may want to get their yearly flu shot a little sooner. For example:

Why Flu Shots Don’t Always Work Well

Despite waning immunity over time, the CDC still says that one flu shot is enough to get the general population through an entire flu season.

“This is part of the reason CDC suggested that older individuals get vaccinated in October rather than being first in line to get them in July or August,” said Creech. “We do not fully know the characteristics of waning immunity in children, but it is clear that vaccinating in the fall protects children through the influenza season, even when it extends into the very late spring.”

Who Should Not Get Flu Shots?

Which Flu Shot Should You Get?

The CDC recommends that everyone over the age of 6 months get their flu shot. Theflu vaccinesfor the season are available at providers’ offices, pharmacies, and even grocery stores. Ifyou’re over the age of 65, the CDC recommends that you get one of the three high-dose vaccines:

While you most likely only need to get one flu shot per flu season,timing matters. Remember that it takes about two weeks after you get vaccinated for immunity to kick in.

What This Means For YouAnnual influenza vaccines are recommended for everyone aged 6 months and older. The only group that needs more than one flu shot per season (two doses spaced four weeks apart) is kids between the ages of 6 months and 8 years old who haven’t gotten a flu shot before.People over the age of 65 should get one of three high-dose flu vaccines available to ensure they get the best protection. Getting your flu shot in the months of September and October helps make sure you have protection through peak flu season into the spring.

What This Means For You

Annual influenza vaccines are recommended for everyone aged 6 months and older. The only group that needs more than one flu shot per season (two doses spaced four weeks apart) is kids between the ages of 6 months and 8 years old who haven’t gotten a flu shot before.People over the age of 65 should get one of three high-dose flu vaccines available to ensure they get the best protection. Getting your flu shot in the months of September and October helps make sure you have protection through peak flu season into the spring.

Annual influenza vaccines are recommended for everyone aged 6 months and older. The only group that needs more than one flu shot per season (two doses spaced four weeks apart) is kids between the ages of 6 months and 8 years old who haven’t gotten a flu shot before.

People over the age of 65 should get one of three high-dose flu vaccines available to ensure they get the best protection. Getting your flu shot in the months of September and October helps make sure you have protection through peak flu season into the spring.

Which Flu Shot Should I Get If I’m Over 65?

10 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Centers for Disease Control and Prevention.How influenza (flu) vaccines are made.Centers for Disease Control and Prevention.Selecting viruses for the seasonal influenza vaccine.Centers for Disease Control and Prevention.Vaccine effectiveness: how well do flu vaccines work?.Bosaeed M, Kumar D.Seasonal influenza vaccine in immunocompromised persons.Hum Vaccin Immunother. 2018;14(6):1311-1322. doi:10.1080/21645515.2018.1445446Cordero E, Roca-Oporto C, Bulnes-Ramos A, et al.Two doses of inactivated influenza vaccine improve immune response in solid organ transplant recipients: results of TRANSGRIPE 1-2, a randomized controlled clinical trial.Clin Infect Dis. 2017;64(7):829-838. doi:10.1093/cid/ciw855Immunization Action Coalition.What to do if the wrong dose of a vaccine is administered.Immunization Action Coalition.Ask the experts: influenza.Centers for Disease Control and Prevention.Frequently asked influenza (flu) questions: 2022-2023 season.Centers for Disease Control and Prevention.Inactivated influenza VIS.Centers for Disease Control and Prevention.Who needs a flu vaccine.

10 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Centers for Disease Control and Prevention.How influenza (flu) vaccines are made.Centers for Disease Control and Prevention.Selecting viruses for the seasonal influenza vaccine.Centers for Disease Control and Prevention.Vaccine effectiveness: how well do flu vaccines work?.Bosaeed M, Kumar D.Seasonal influenza vaccine in immunocompromised persons.Hum Vaccin Immunother. 2018;14(6):1311-1322. doi:10.1080/21645515.2018.1445446Cordero E, Roca-Oporto C, Bulnes-Ramos A, et al.Two doses of inactivated influenza vaccine improve immune response in solid organ transplant recipients: results of TRANSGRIPE 1-2, a randomized controlled clinical trial.Clin Infect Dis. 2017;64(7):829-838. doi:10.1093/cid/ciw855Immunization Action Coalition.What to do if the wrong dose of a vaccine is administered.Immunization Action Coalition.Ask the experts: influenza.Centers for Disease Control and Prevention.Frequently asked influenza (flu) questions: 2022-2023 season.Centers for Disease Control and Prevention.Inactivated influenza VIS.Centers for Disease Control and Prevention.Who needs a flu vaccine.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Centers for Disease Control and Prevention.How influenza (flu) vaccines are made.Centers for Disease Control and Prevention.Selecting viruses for the seasonal influenza vaccine.Centers for Disease Control and Prevention.Vaccine effectiveness: how well do flu vaccines work?.Bosaeed M, Kumar D.Seasonal influenza vaccine in immunocompromised persons.Hum Vaccin Immunother. 2018;14(6):1311-1322. doi:10.1080/21645515.2018.1445446Cordero E, Roca-Oporto C, Bulnes-Ramos A, et al.Two doses of inactivated influenza vaccine improve immune response in solid organ transplant recipients: results of TRANSGRIPE 1-2, a randomized controlled clinical trial.Clin Infect Dis. 2017;64(7):829-838. doi:10.1093/cid/ciw855Immunization Action Coalition.What to do if the wrong dose of a vaccine is administered.Immunization Action Coalition.Ask the experts: influenza.Centers for Disease Control and Prevention.Frequently asked influenza (flu) questions: 2022-2023 season.Centers for Disease Control and Prevention.Inactivated influenza VIS.Centers for Disease Control and Prevention.Who needs a flu vaccine.

Centers for Disease Control and Prevention.How influenza (flu) vaccines are made.

Centers for Disease Control and Prevention.Selecting viruses for the seasonal influenza vaccine.

Centers for Disease Control and Prevention.Vaccine effectiveness: how well do flu vaccines work?.

Bosaeed M, Kumar D.Seasonal influenza vaccine in immunocompromised persons.Hum Vaccin Immunother. 2018;14(6):1311-1322. doi:10.1080/21645515.2018.1445446

Cordero E, Roca-Oporto C, Bulnes-Ramos A, et al.Two doses of inactivated influenza vaccine improve immune response in solid organ transplant recipients: results of TRANSGRIPE 1-2, a randomized controlled clinical trial.Clin Infect Dis. 2017;64(7):829-838. doi:10.1093/cid/ciw855

Immunization Action Coalition.What to do if the wrong dose of a vaccine is administered.

Immunization Action Coalition.Ask the experts: influenza.

Centers for Disease Control and Prevention.Frequently asked influenza (flu) questions: 2022-2023 season.

Centers for Disease Control and Prevention.Inactivated influenza VIS.

Centers for Disease Control and Prevention.Who needs a flu vaccine.

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