Which Flu Shot Is the Most Effective for the 2021-2022 Flu Season?

Health Conditions

Which Flu Shot Is the Most Effective for the 2021-2022 Flu Season?

Cold & Flu Season.The Flu
Christina Aungst, PharmD
By Christina Aungst, PharmD
Sept 20, 2021
Which Flu Shot Is the Most Effective for the 2021-2022 Flu Season?

Key takeaways:

  • There are nine flu vaccines available for the 2021-2022 flu season.
  • Some flu vaccines may be a better option for certain people, including older adults and those with egg allergies.
  • It’s best to get your flu vaccine by the end of October, but getting vaccinated later than that is still beneficial.

With flu season beginning to pick up in October, you’ve probably been seeing signs or advertisements telling you to get your annual flu shot. But with several flu vaccine options to choose from, it can be confusing to know which one to pick. Does it really make a difference which one you get?

If you’re feeling overwhelmed or a little confused about which flu vaccine you should get, you’re not alone. Stick with us as we discuss the available flu vaccine options this year, possible advantages to certain vaccines, and the expected flu vaccine effectiveness.

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What you need to know about the 2021-2022 flu season

While no one knows for sure just how bad the upcoming flu season will be, here’s some flu information we know so far:

  • The 2020-2021 flu season was unusually mild compared to what’s been seen in past years. This could be due to multiple factors, including higher flu vaccination rates during 2020 and the effect the COVID-19 pandemic has had on social distancing and hand washing. Experts are not sure if this will be the case again for the 2021-2022 flu season.

  • Flu transmission rates in other countries are lower than usual so far this year. The World Health Organization (WHO) meets twice a year — in February and September — to review flu activity around the world and recommend which strains to include in the flu vaccine. Flu transmission in the Southern Hemisphere countries — like Australia — can help predict what the U.S. flu season might be like. Australia had a record low number of cases of the flu during 2021. Hopefully, that means we will too.

  • Even though the flu vaccine doesn’t protect against all strains of the flu, it’s still recommended for everyone over the age of 6 months. The flu vaccine is typically about 40% to 60% effective, and it’s hard to predict if the current flu vaccines will be a good match for the strains going around. But it’s still one of the best ways to help prevent getting sick with the flu.

What vaccines are available for the 2021-2022 flu seasons?

There are nine vaccines that have been approved and released by the FDA for the 2021-2022 flu season. This year, all FDA-approved flu vaccines are quadrivalent — meaning they protect against four different strains of influenza (the virus that causes the flu). Here’s a rundown of the available flu vaccines for the year.

Vaccine name Age range How it’s given Potential allergens
Afluria Quadrivalent (FDA package insert) 6 months or older Intramuscular Egg protein, neomycin, polymyxin
Fluad Quadrivalent (FDA package insert) 65 years or older Intramuscular Egg protein, kanamycin, neomycin, polysorbate 80
Fluarix Quadrivalent (FDA package insert) 6 months or older Intramuscular Egg protein, gentamicin, polysorbate 80
Flublok Quadrivalent (FDA package insert) 18 years or older Intramuscular Polysorbate 20
Flucelvax Quadrivalent (FDA package insert) 2 years or older Intramuscular Polysorbate 80
FluLaval Quadrivalent (FDA package insert) 6 months or older Intramuscular Egg protein, polysorbate 80
FluMist Quadrivalent (FDA package insert) 2-49 years Nasal spray Egg protein, gentamicin, pork gelatin
Fluzone High-Dose Quadrivalent (FDA package insert) 65 years or older Intramuscular Egg protein
Fluzone Quadrivalent (FDA package insert) 6 months or older Intramuscular Egg protein

It’s important to note that pharmacies and healthcare providers may only carry a few brands of flu vaccine — not all nine that are FDA-approved. If you are interested in or know you need a certain flu vaccine, it’s best to call ahead and see if your preferred vaccine is available.

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Which flu vaccine is the most effective?

When flu vaccines are being produced, the strains included are standardized by the FDA. Each 2021-2022 vaccine includes:

  • Two type A flu viruses (H1N1 and H3N2)
  • Two type B viruses (Victoria and Yamagata lineages) This means that no matter what vaccine you choose, you’re being protected against the same strains. Flu vaccines are typically between 40% and 60% effective from year to year. But when it comes to picking the right flu vaccine for you, you have to take other factors into account.

The best flu vaccine for people over 65

As we get older, our immune systems have a harder time responding to illnesses and vaccines. To help provide better protection, there are a few recommended options for older adults this year:

  • Fluzone High-Dose Quadrivalent — also known as the “high-dose flu shot”
  • Fluad Quadrivalent
  • Flublok Quadrivalent If one of these three vaccines isn’t available, you should still get vaccinated with another flu vaccine that’s FDA-approved for your age range. All flu vaccines are effective against the flu. It’s better to be vaccinated than to try to wait for a particular flu vaccine to become available.

The best flu vaccine if you have egg allergies

Many flu vaccines are made using chicken eggs — called egg-based vaccines. While most people with egg allergies are still able to receive egg-based flu vaccines, there are rare instances where they can cause life-threatening allergic reactions. If this is the case for you or if you’re concerned, Flucelvax Quadrivalent and Flublok Quadrivalent are two egg-free flu vaccine options.

The best flu vaccine if you’re scared of needles

While most people use the terms “flu vaccine” and “flu shot” interchangeably, not all flu vaccines use a needle to deliver the ingredients.

FluMist Quadrivalent is a nasal spray vaccine. However, it’s not the right choice for some people. This vaccine is only FDA-approved for people between ages 2 and 49. FluMist Quadrivalent is also a live attenuated vaccine, meaning it contains weakened versions of the flu viruses instead of inactivated (dead) viruses. People who are pregnant and those with certain health problems — such as a weakened immune system — shouldn’t receive it.

How long does the flu vaccine last?

Flu vaccine immunity — meaning immune system protection — doesn’t last long. After about 6 months, your immunity starts to fade. This falling level of protection (from a lessening amount of antibodies), combined with ever-mutating flu viruses, means it’s important to be vaccinated for the flu every year.

When should I get my flu vaccine?

Flu vaccine effectiveness can have a lot to do with when you get it. It’s recommended to get your flu vaccine about 2 weeks before flu season begins in your area — preferably by the end of October. However, if you get the flu vaccine too early — July or August, for instance — you may not be protected for the entire flu season.

While September or October are the ideal times to get your flu vaccine, it’s still recommended to get it later than that if you were unable to do so earlier. If you’re unsure when flu season begins in your area, talk to your local pharmacist or healthcare provider.

If you’ve recently received or will be receiving a COVID-19 vaccine — including booster doses — you don’t have to wait a certain time to get the flu vaccine. You can even get them on the same day, if that’s more convenient. These two vaccines aren’t known to interfere with each other.

Can I get the flu from the flu vaccine?

No. The virus that’s in the flu vaccine is either dead or — for FluMist Quadrivalent — extremely weak. Because of this, flu vaccines are unable to cause the flu. However, some people experience flu-like symptoms in the days that follow their vaccine. These are side effects of the flu vaccine, and it’s a sign your immune system is learning how to fight the flu virus.

After your flu vaccine, you may experience:

  • A sore, red, or swollen arm
  • A headache
  • Low fever
  • Muscle aches
  • Tiredness Remember, these are expected side effects and don’t mean you’re getting sick with the flu. They should go away within a few days.

Unfortunately, it’s still possible to get sick with the flu after you’ve received your flu vaccine. It takes about 2 weeks after your vaccine for your immune system to protect you fully. So it’s possible to catch the flu during that time. And as mentioned earlier, flu vaccine effectiveness isn’t perfect. It’s also possible to get sick with a strain that wasn’t included in the vaccine.

The bottom line

There are nine options for flu vaccines for the 2021-2022 flu season. No matter which you choose, flu vaccine effectiveness should be the same. Some flu vaccines may be a better choice for certain groups of people, such as older adults and people with life-threatening egg allergies. If you’re still questioning which flu vaccine is right for you, make it a point to talk to your healthcare provider and get vaccinated this fall.

Christina Aungst, PharmD

Christina Aungst, PharmD

Christina is a pharmacy editor for GoodRx. She received her Doctor of Pharmacy from Wilkes University in Wilkes-Barre, Pennsylvania and is licensed in the states of Massachusetts and Pennsylvania. Prior to writing for GoodRx, she helped build clinical content for Iodine.com. Her professional areas of interest include women's health, mental health, and infectious disease medicine.

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