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Influenza Vaccine


Margot L. Savoy

, MD, MPH, Lewis Katz School of Medicine at Temple University

Reviewed/Revised Jul 2023

Based on recommendations by the World Health Organization and the Centers for Disease Control and Prevention (CDC), vaccines for influenza Influenza Influenza is a viral respiratory infection causing fever, coryza, cough, headache, and malaise. Mortality is possible during seasonal epidemics, particularly among high-risk patients (eg, those... read more are modified annually to include the most prevalent strains (usually 2 strains of influenza A and 1 or 2 strains of influenza B). Sometimes slightly different vaccines are used in the northern and southern hemispheres.

For more information, see the Centers for Disease Control and Prevention (CDC) Influenza Advisory Committee on Immunization Practices Vaccine Recommendations and CDC: Influenza Vaccination. For a summary of changes to the 2023 adult immunization schedule, see the Advisory Committee on Immunization Practices Recommended Adult Immunization Schedule, United States, 2023: Changes to the 2023 Adult Immunization Schedule.

Preparations of Influenza Vaccine

There are 2 basic types of influenza virus vaccine:

  • Inactivated influenza vaccine (IIV)

  • Live-attenuated influenza vaccine (LAIV)

Trivalent vaccines are gradually being superseded by quadrivalent vaccines that cover an additional B virus strain. A quadrivalent recombinant influenza vaccine (RIV4) and a cell culture–based vaccine (ccIIV4) that do not contain egg protein are available. High-dose quadrivalent vaccines are available for patients ≥ 65 years of age. (See also CDC: Different Types of Flu Vaccines.)

Indications for Influenza Vaccine

Annual vaccination against influenza with an age-appropriate formulation is recommended for all people ≥ 6 months of age who do not have a contraindication. (See CDC: Child and Adolescent Immunization Schedule by Age and CDC: Adult Immunization Schedule by Age.)

Inactivated influenza vaccine (IIV) can be given to all people ≥ 6 months, including pregnant women.

Recombinant influenza vaccine (RIV4) can be used in people aged 18 to 49 years.

Live-attenuated influenza vaccine (LAIV) can be given to healthy people aged 2 to 49 years who are not pregnant and who do not have immunocompromising conditions. Safety of LAIV has not been established in people with disorders that predispose them to complications from influenza, including advanced lung disease or asthma.

Adults ≥ 65 years should be given any one of the quadrivalent high-dose IIV, quadrivalent recombinant influenza vaccine, or quadrivalent adjuvanted IIV. If none of these are available, then any other age-appropriate influenza vaccine should be used. The high dose is recommended only for those ≥ 65 years.

Health care workers who care for immunocompromised people (ie, those who require care in a protected environment) should be given IIV or RIV4 rather than LAIV (or they should avoid contact with the immunocompromised people for 7 days after getting the vaccine).

Contraindications and Precautions for Influenza Vaccine

The main contraindication for IIV is

Precautions with IIV include

Contraindications for LAIV include

Precautions for LAIV include

The main contraindication for RIV4 is

  • A severe allergic reaction (eg, anaphylaxis) after a previous dose of RIV4

Precautions with RIV4 include

  • Moderate or severe acute illness with or without fever (vaccination is postponed until illness resolves)

  • Guillain-Barré syndrome within 6 weeks after a previous dose of an influenza vaccine

Precautions for patients with suspected egg allergy: Patients with a history of egg allergy who have had only hives after exposure to egg should be given the influenza vaccine. Any influenza vaccine that is otherwise recommended based on the recipient’s age and health status can be used.

Patients who report reactions to egg involving symptoms other than hives (such as angioedema, respiratory distress, light-headedness, or recurrent emesis) or who required epinephrine or another emergency medical intervention may similarly be given any influenza vaccine that is otherwise recommended based on the recipient’s age and health status. If using an egg-based vaccine such as IIV or LAIV, the vaccine should be given in a medical setting and supervised by a health care professional capable of recognizing and managing severe allergic conditions.

Dose and Administration of Influenza Vaccine

The influenza vaccine is given yearly.

For IIV, the dose is

  • 0.25 mL or 0.50 mL IM (depending on vaccine) for children aged 6 to 35 months

  • 0.5 mL IM for people ≥ 3 years

  • 0.1 mL for people aged 18 to 64 years, given intradermally

Children age 6 months to 8 years who have received fewer than 2 influenza vaccine doses or whose influenza vaccination history is unknown should receive 2 doses, separated by at least 4 weeks.

The smaller, intradermal dose can be used to conserve vaccine in times of shortage.

For LAIV, the dose is 0.1 mL, sprayed into each nostril (total dose is 0.2 mL).

For RIV4, the dose is 0.5 mL IM.

Adverse Effects of Influenza Vaccine

For IIV, adverse effects are usually limited to mild pain at the injection site. Fever, myalgia, and other systemic effects are relatively uncommon; however, people who have been vaccinated may mistakenly think that the vaccine is causing influenza. Such reactions do not contraindicate future vaccination, which should be encouraged.

Multidose vials contain thimerosal, a mercury-based preservative. Public concerns about a possible link between thimerosal and autism Thimerosal and Autism Despite the rigorous vaccine safety systems in place in the United States, some parents remain concerned about the safety of the use and schedule of vaccines in children. These concerns have... read more have proved unfounded; however single-dose vials, which are thimerosal-free, are available.

For LAIV, adverse effects are mild; rhinorrhea is the most common, and mild wheezing may occur.

More Information

The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.

Drugs Mentioned In This Article

Drug Name Select Trade
Afluria , Afluria Quadrivalent, Agriflu, Alfuria, FLUAD, FLUAD Quadrivalent, Fluarix, Fluarix Quadrivalent, Flublok, Flublok Quadrivalent, FLUCELVAX, FLUCELVAX Quadrivalent, Flulaval, Flulaval Quadrivalent, Fluogen, Flushield, Fluvirin, Fluzone, Fluzone High-Dose, Fluzone Intradermal, Fluzone Quadrivalent
Anacin Adult Low Strength, Aspergum, Aspir-Low, Aspirtab , Aspir-Trin , Bayer Advanced Aspirin, Bayer Aspirin, Bayer Aspirin Extra Strength, Bayer Aspirin Plus, Bayer Aspirin Regimen, Bayer Children's Aspirin, Bayer Extra Strength, Bayer Extra Strength Plus, Bayer Genuine Aspirin, Bayer Low Dose Aspirin Regimen, Bayer Womens Aspirin , BeneHealth Aspirin, Bufferin, Bufferin Extra Strength, Bufferin Low Dose, DURLAZA, Easprin , Ecotrin, Ecotrin Low Strength, Genacote, Halfprin, MiniPrin, St. Joseph Adult Low Strength, St. Joseph Aspirin, VAZALORE, Zero Order Release Aspirin, ZORprin
GOCOVRI, Osmolex ER, Symmetrel
Adrenaclick, Adrenalin, Auvi-Q, Epifrin, EpiPen, Epipen Jr , Primatene Mist, SYMJEPI, Twinject
NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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