Page 1 | 2Influenza Vaccine

Types of Influenza Vaccine

There are three types of influenza vaccines: an injectible shot; an intradermal (under the skin) vaccine and a nasal spray vaccine. Each season three strains of virus are included in the influenza vaccine; two type A viruses and one B virus. For the quadrivalent vaccine, an additional B virus virus is included.

Inactivated influenza vaccine or IIV - The inactivated influenza shot contains killed virus. Influenza shots are approved for use in people 6 months and older, including healthy people and people with chronic medical conditions. There are different types of the influenza shots available, including a high-dose vaccine for people 65 years of age and older. The high-dose vaccine is not recommended for people who have had a severe reaction to the influenza vaccine in the past.

The intradermal influenza vaccine is approved for people 18-64 years of age. The intradermal vaccine is injected into the skin instead of the muscle.

Live attenuated influenza vaccine or LAIV - The nasal spray vaccine or LAIV contains the same three virus strains but are weakened live viruses. LAIV is approved for use in healthy people 2-49 years of age who are not pregnant.

NOTE:Based on the evidence for poor effectiveness of LAIV in the US over the last several influenza seasons, for the 2016-17 season, ACIP has made the interim recommendation that LAIV (FluMist) should not be used. For more information, visit

Cell-based influenza vaccine - 'Cell-based’ refers to how the influenza vaccine is made. Cell-based influenza vaccines are made by growing viruses in animal cells, rather than in fertilized chicken eggs. The current cell-based influenza vaccine, Flucelvex, is licensed for use in individuals 18 years of age and older.

Jet injector influenza vaccine - A jet injector is a medical device used for vaccination that uses a high-pressure, narrow stream of fluid to penetrate the skin instead of a hypodermic needle. The one influenza vaccine currently approved for use with a jet injector this season, AFLURIA®, is a trivalent ( three strain) influenza vaccine. It is approved for use in people 18 through 64 years of age.

Quadrivalent influenza vaccine - The quadrivalent influenza vaccine is designed to protect against four different influenza viruses; two influenza A viruses and two influenza B viruses. There is a standard-dose quadrivalent shot that can be given to children as young as 6 months of age. Other standard-dose quadrivalent shots are approved for people 3 years and older. The standard-dose quadrivalent nasal spray vaccine is approved for healthy people 2 through 49 years of age.

Influenza Vaccine Virus Strains

The World Health Organization (WHO) recommended that the Northern Hemisphere's 2016-2017 seasonal influenza vaccine contain the following three vaccine viruses:

  • an A/California/7/2009 (H1N1)pdm09-like virus;
  • an A/Hong Kong/4801/2014 (H3N2)-like virus;
  • a B/Brisbane/60/2008-like virus (B/Victoria lineage).

It was recommended that quadrivalent vaccines containing two influenza B viruses contain the above three viruses and a B/Phuket/3073/2013-like virus (B/Yamagata lineage).

Influenza Vaccine Recommendations

To read the 2016-2017 influenza vaccine recommendations, visit the Centers for Disease Control and Prevention (CDC).

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