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.
(See also Overview of Immunization Overview of Immunization Immunity can be achieved Actively by using antigens (eg, vaccines, toxoids) Passively by using antibodies (eg, immune globulins, antitoxins) A toxoid is a bacterial toxin that has been modified... read more .)
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Trivalent vaccines are gradually being superseded by quadrivalent vaccines that cover an additional B virus strain.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
A severe allergic reaction (eg, anaphylaxis Anaphylaxis Anaphylaxis is an acute, potentially life-threatening, IgE-mediated allergic reaction that occurs in previously sensitized people when they are reexposed to the sensitizing antigen. Symptoms... read more ) after previous dose of IIV or to a vaccine component, including egg protein
Precautions with IIV include
Moderate or severe acute illness with or without fever (vaccination is postponed until illness resolves)
Guillain-Barré syndrome Guillain-Barré Syndrome (GBS) Guillain-Barré syndrome is an acute, usually rapidly progressive but self-limited inflammatory polyneuropathy characterized by muscular weakness and mild distal sensory loss. Cause is thought... read more (GBS) within 6 weeks after a previous dose of an influenza vaccine
Contraindications for LAIV include
A severe allergic reaction (eg, anaphylaxis) to any vaccine component (excluding egg) or to a previous dose of any influenza vaccine
Immunocompromise (eg, due to disorders, including HIV infection, or use of immunosuppressants)
For children and adolescents, concomitant use of aspirin or other salicylates
Close contact with and/or caring for severely immunocompromised patients who require a protected environment (unless contact is avoided for 7 days after receiving LAIV)
Pregnancy
Receipt of influenza antiviral drugs in the past 48 hours
Cerebrospinal fluid leak or a cochlear implant
Age < 2 years or ≥ 50 years
Age 2 to 4 years if children have asthma or have had wheezing or asthma episodes in the past 12 months
Precautions for LAIV include
Certain chronic disorders such as chronic lung, heart, kidney, liver, hematologic (eg, hemoglobinopathies), or metabolic (eg, diabetes mellitus) disorders
Asthma in people aged ≥ 5 years
Moderate or severe acute illness with or without fever (vaccination is postponed until illness resolves)
Guillain-Barré syndrome Guillain-Barré Syndrome (GBS) Guillain-Barré syndrome is an acute, usually rapidly progressive but self-limited inflammatory polyneuropathy characterized by muscular weakness and mild distal sensory loss. Cause is thought... read more within 6 weeks after a previous dose of an influenza vaccine
Use of specific antiviral drugs: ie, amantadine, rimantadine, zanamivir, oseltamivir (these drugs are stopped 48 hours before vaccination and are not resumed for 14 days after vaccination)
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.
Advisory Committee on Immunization Practices (ACIP): Influenza ACIP Vaccine Recommendations
ACIP: Recommended Adult Immunization Schedule, United States, 2023 including Changes to the 2023 Adult Immunization Schedule
Centers for Disease Control and Prevention (CDC): Influenza Vaccination: Information for Healthcare Professionals
European Centre for Disease Prevention and Control (ECDC): Influenza: Recommended vaccinations
Drugs Mentioned In This Article
| Drug Name | Select Trade |
|---|---|
influenza virus vaccine |
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 |
aspirin |
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 |
amantadine |
GOCOVRI, Osmolex ER, Symmetrel |
rimantadine |
Flumadine |
zanamivir |
Relenza |
oseltamivir |
Tamiflu |
epinephrine |
Adrenaclick, Adrenalin, Auvi-Q, Epifrin, EpiPen, Epipen Jr , Primatene Mist, SYMJEPI, Twinject |
