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Types of Available Flu Vaccines for the 2020-2021 Flu Season

Posted on September 17, 2020
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Everyone six months and older, with rare exception, should get an annual flu vaccine, but there are many different options available. So how can you decide which one is right for you? All available flu vaccines on the market help protect against the same three or four circulating flu strains in the United States, but there are different vaccine types that may be recommended based on a recipient’s age, medical history, medical conditions, and allergies.

Regardless of which type of flu vaccine may be right for you, flu vaccines do not contain viruses that can make you sick with flu, so it’s impossible for the flu vaccine to cause the flu. Some people may experience mild side effects following vaccination, such as redness and slight swelling at the injection site, fever, headache, and/or muscle aches. This is not the flu, but actually evidence that your body is having an immune response and preparing to fight off future flu infections.


Flu Vaccines for Most People: Quadrivalent Inactivated Influenza Vaccines (IIV4)

  • All currently available flu vaccines in the U.S., with the exception of one designed specifically for seniors, are quadrivalent. This means that they help protect against four strains of flu: two strains of influenza A (H1N1 and H3N2) and two strains of influenza B.
  • The four flu strains included in the vaccine are the ones most likely to be circulating.
  • The IIV4 vaccine, commonly referred to as the flu shot, is considered “inactivated” because it does not contain any live flu virus.
  • Most quadrivalent vaccines can be given to people ages 6 months and older.
  • Children ages 6 months through 8 years who have never received a flu vaccine before need two doses spaced out by at least 28 days.


Flu Vaccines for Seniors: Adjuvanted Trivalent and Quadrivalent Inactivated Influenza Vaccines (aIIV3, aIIV4) and High-Dose Quadrivalent Inactivated Influenza Vaccines (IIV4-HD)

  • Annual flu vaccination is important for people who are 65 years and older because they are more likely to suffer from severe flu-related outcomes like hospitalization and death.
  • Flu vaccines that are designed specifically for people ages 65 years and older contain either higher doses of antigens or ingredients called adjuvants.
    • Antigens help your body create antibodies that fight off flu.
    • Adjuvants are specific ingredients used to improve immune responses without additional antigens.
  • High-dose flu vaccines contain a higher amount of antigens. This year, the high-dose senior vaccine helps protect against four strains of flu.
  • Adjuvanted senior vaccines are available as either trivalent (helps protect against three strains of flu) or quadrivalent (helps protect against four strains of flu).

Nasal Spray Flu Vaccine: Quadrivalent Live Attenuated Influenza Vaccine (LAIV4)

  • The nasal spray vaccine can be used in individuals ages 2 through 49 years and can be a good option for people who avoid flu vaccination due to a fear of needles.
  • The vaccine is known as live attenuated” because it includes tiny bits of weakened, live viruses that are modified so that they can replicate in the nose to create an immune response.
  • These weakened, live viruses are safe because they cannot replicate in the warm conditions of the lungs, which means the vaccine cannot cause flu illness.
  • This vaccine cannot be used by people with certain health conditions, such as those with asthma and pregnant women.
  • To learn more about the nasal spray flu vaccine and who is eligible to receive it, please visit the CDC’s website here.


Egg-Free Flu Vaccines: Recombinant and Cell-Based Vaccines

  • It is a common misconception that people who are allergic to eggs cannot receive an influenza vaccine, but people who have only experienced hives following egg exposure may receive any age-appropriate, licensed flu vaccine.
  • While most flu vaccines are still manufactured using eggs, there are currently two egg-free flu vaccines available for individuals 4 years of age and older: recombinant and cell-based.
    • Recombinant vaccines use insect cells rather than eggs to grow flu viruses during the manufacturing process.
    • Cell-based vaccines use mammalian cells to grow the flu virus.
  • Both recombinant and cell-based vaccines provide protection against four strains of influenza.
  • Learn more about how flu vaccines are made here.

It’s always best to talk to your trusted healthcare professional about which flu vaccine is best for you. For help finding a flu vaccine near you, visit the Vaccine Finder.

Flu Vaccine Products Available for the 2020-2021 Season*

* The information is listed here for educational purposes only. Families Fighting Flu does not advocate on behalf of the use of any particular flu vaccine product. Please consult your trusted healthcare professional to determine which flu vaccine is appropriate for you.

** Egg-free

*** Multiple products are available and age restrictions are based on dosage (single-dose syringe/vial, multi-dose vial).

LAIV4 = quadrivalent live attenuated influenza vaccine

IIV4 = quadrivalent inactivated influenza vaccine

RIV4 = recombinant quadrivalent inactivated influenza vaccine

IIV4-HD = quadrivalent inactivated influenza vaccine, high-dose

aIIV3 = trivalent, adjuvanted inactivated influenza vaccine

aIIV4 = quadrivalent, adjuvanted inactivated influenza vaccine

ccIIV4 = quadrivalent, cell-cultured inactivated influenza vaccine









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