Mission: To save lives and reduce hospitalizations by protecting children, families, and communities against influenza.

Types of Flu Vaccines

Learn which flu vaccines are best for you based on your age and medical conditions. 

Quadrivalent Inactivated Influenza Vaccines (IIV4)

Quadrivalent Inactivated Influenza Vaccines (IIV4)

The most commonly administered flu vaccine is a quadrivalent vaccine, which provides protection against the four strains of influenza most likely to be circulating each season.


Trivalent Inactivated Influenza Vaccines (IIV3)

Trivalent Inactivated Influenza Vaccines (IIV3)

These flu vaccines provide protection against three strains of influenza (as opposed to four with a quadrivalent vaccine). There are no trivalent vaccines for the 2021-2022 flu season.


nasal spray flu vaccine

Quadrivalent Live Attenuated Influenza Vaccine (LAIV4)

Nasal Spray Flu Vaccine

This vaccine is administered intranasally, which means that the vaccine is sprayed up the nose as opposed to being injected with a needle. 

This 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 minuscule bits of weakened, live viruses that are modified in such a way that they can replicate in the nose to create an immune response without infecting you with a flu illness. Some people do not qualify for the nasal spray vaccine.

Influenza vaccination and fear of needles

Piper had not been vaccinated against the flu because she did not like needles. Her mother, Pegy, is now an active advocate for annual flu vaccinations.

Read Piper's Story


Quadrivalent Recombinant Influenza Vaccine (RIV4)

Quadrivalent Recombinant Influenza Vaccine (RIV4)

Recombinant vaccines do not use chicken eggs in the manufacturing process, similar to cell-cultured vaccines. Because these vaccines are not dependent on an egg supply or limited by the selection of vaccine viruses that are adapted for growth in eggs, recombinant vaccines can be useful in the event of a pandemic or vaccine supply shortage.


Quadrivalent Recombinant Influenza Vaccine (RIV4)

Quadrivalent Cell-Cultured Influenza Vaccine (ccIIV4)

Cell-cultured (also known as cell-based) vaccines do not use chicken eggs in the manufacturing process, similar to recombinant vaccines. The manufacturing process of these vaccines uses animal cells to grow flu viruses instead of eggs.
Kathy Pool, protect your family with flu vaccination

Kathy Pool encourages other grandparents to get a flu vaccine specifically designed for seniors to protect themselves and everyone they love from going through what her granddaughter, Caroline, experienced.

Read Caroline's Story

Flu Vaccines for Seniors

As our body ages, so does our immune system. That is why there are specific vaccines for individuals 65 years and older to create a stronger immune response against the flu.

Talk to your health care provider about which vaccine is best for you.

3 Ways Flu Vaccines are Manufactured:

Egg-based vaccines

Egg-Based Flu Vaccines

The egg-based vaccine manufacturing process has been used for more than 70 years. This process is used to make many of the inactivated flu vaccines (i.e., flu shots) as well as the live attenuated influenza vaccine (LAIV, or the nasal spray flu vaccine). The manufacturing process begins with the Centers for Disease Control and Prevention (CDC) or the World Health Organization (WHO) providing egg-grown candidate vaccine viruses (CVVs) to manufacturers. These CVVs are then injected into fertilized chicken eggs and allowed to replicate. The virus-containing fluid is then harvested from the eggs. For flu shots, the vaccine viruses are then inactivated and the virus antigen is purified. The manufacturing process continues with purification and testing. For LAIV, the starting CVVs are weakened viruses and go through a different production process. The U.S. Food and Drug Administration (FDA) tests and approves vaccines prior to release and shipment.

Even individuals with confirmed egg allergy can safely receive egg-based flu vaccines. The American Academy of Allergy Asthma and Immunology, the American College of Allergy Asthma and Immunology as well as the American Academy of Pediatrics and the CDC state that no special precautions are required for the administration of influenza vaccine to egg-allergic patients. Learn more about the safety of flu vaccines for people with egg allergies.

Cell-based vaccines

Cell-Based Flu Vaccines

The cell-based vaccine manufacturing process uses animal cells in liquid culture to grow influenza viruses in place of fertilized chicken eggs. The manufacturing process begins when the World Health Organization (WHO) recommends cell-grown candidate vaccine viruses (CVVs) for distribution to manufacturers. The manufacturers then inoculate these CVVs into cultured mammalian cells (instead of eggs) and allow them to replicate for a few days. Then the virus-containing fluid is collected from the cells and the virus antigen is purified. The manufacturing process continues with purification and testing before the U.S. Food and Drug Administration (FDA) tests and approves the vaccines prior to release and shipment.

Recombinant Flu Vaccines

Recombinant Flu Vaccines

The recombinant manufacturing process does not use chicken eggs at all in the production process. Instead, manufacturers isolate a certain gene from a naturally occurring "wild type" recommended vaccine virus. The gene is then combined with portions of another virus that grows well in insect cells to make a "recombinant" vaccine virus. The vaccine virus is then mixed with insect cells and allowed to replicate. The flu protein is then harvested from these cells, purified, and submitted for testing and approval to the U.S. Food and Drug Administration (FDA) prior to release and shipment.

Page last reviewed: October 2021.

Stay Informed
Sign up for our Weekly Flu News and quarterly newsletter, Fighting Influenza, to stay up-to-date on the latest flu news.


You are required to accept all of the terms and conditions in this License Agreement in order to receive a limited, non-exclusive, non-transferable, non-assignable, royalty-free license to use the FAMILIES FIGHTING FLU, INC. logo, displayed below (the “FFF Logo”), from Families Fighting Flu, Inc. (“FFF”). In order to accept these terms and conditions, you must click the “I Accept” button below.

  1. FFF hereby grants to you, and you accept, a limited, non-exclusive, non-transferable, non-assignable, royalty-free license to use the FFF Logo, which you may download and use solely in online and print earned media publications for a period of no more than six (6) months in the United States.
  2. You acknowledge that the FFF Logo is a valid trademark; that FFF is the sole owner of the FFF Logo; and that FFF retains all right, title, and interest in and to the FFF Logo. You agree that any and all use that you make of the FFF Logo, and any and all goodwill arising from your use of the FFF Logo, shall inure exclusively to the benefit of FFF.  You also agree that you shall not challenge the validity of the FFF Logo or FFF’s ownership or title thereto during the term of the License Agreement or thereafter.
  3. You agree that you shall use the FFF Logo only in the form shown above, and that you shall not alter, modify, change, or edit the FFF Logo in any manner.
  4. You acknowledge the valuable goodwill and reputation in the FFF Logo, and that it is essential that the high standards and reputation associated with the FFF Logo be maintained. You therefore agree to use the FFF Logo consistent with the highest standards of quality so as to protect and maintain the FFF Logo and FFF’s rights therein.
  5. FFF shall have the right to review and inspect your use of the FFF Logo at any time. FFF, in its sole discretion, may determine that you are not using the FFF Logo in an acceptable manner and require that you discontinue your use of the FFF Logo.  To the extent that FFF requires that you discontinue your use of the FFF Logo, you agree that you shall remove the FFF Logo from all online and print earned media publications as soon as practicable under the circumstances, and that you shall not use the FFF at any time in the future.
  6. You must include the following notice in connection with any use of the FFF Logo: “The Families Fighting Flu, Inc. logo is the registered trademark of Families Fighting Flu, Inc.”
I Accept