Influenza Vaccination: A Summary for Clinicians

Who Should Get Vaccinated?

Everyone 6 months of age and older should get a flu vaccine every season. This recommendation has been in place since February 24, 2010 when CDC’s Advisory Committee on Immunization Practices (ACIP) voted for “universal” flu vaccination in the United States to expand protection against the flu to more people.

Vaccination to prevent influenza is particularly important for people who are at high risk of serious complications from influenza. See People at High Risk of Developing Flu-Related Complications for a full list of age and health factors that confer increased risk.

More information is available at Who Should Get Vaccinated Against Influenza.

What are the influenza vaccine options this season?

CDC recommends use of any licensed, age-appropriate influenza vaccine during the 2018-2019 influenza season, including inactivated influenza vaccine [IIV], recombinant influenza vaccine [RIV], or live attenuated influenza vaccine (LAIV). No preference is expressed for any influenza vaccine over another. Both trivalent (three-component) and quadrivalent (four-component) flu vaccines will be available.

Trivalent flu vaccines include:

Quadrivalent flu vaccines include:

  • Standard-dose quadrivalent flu shots that are manufactured using virus grown in eggs.  These include Afluria Quadrivalent, Fluarix Quadrivalent, FluLaval Quadrivalent, and Fluzone Quadrivalent. Different flu shots are approved for different age groups. Some are approved for children as young as 6 months of age. Most flu shots are given in the arm (muscle) with a needle. One quadrivalent flu shot (Afluria Quadrivalent) can be given either with a needle (for people aged 5 years and older) or with a jet injector (for people aged 18 through 64 years only).
  • A quadrivalent cell-based flu shot (Flucelvax Quadrivalent) containing virus grown in cell culture (that is egg-free), which is approved for people 4 years and older.
  • A recombinant quadrivalent flu shot (Flublok Quadrivalent) approved for people 18 years and older.

Package inserts should be consulted for recommended age groups and possible contraindications for each vaccine in addition to information regarding additional components of various vaccine formulations.

In addition, the Advisory Committee on Immunization Practices (ACIP), Influenza Vaccine Recommendations, 2016-17 should be consulted.

Are any of the available flu vaccines recommended over others?

For the 2018-2019 flu season, the Advisory Committee on Immunization Practices (ACIP) recommends annual influenza vaccination for everyone 6 months and older with any licensed age-appropriate flu vaccine including inactivated influenza vaccine (IIV), recombinant influenza vaccine (RIV4) or live attenuated influenza vaccine (LAIV4) with no preference expressed for any one vaccine over another.

When should vaccination occur?

You should get a flu vaccine before flu begins spreading in your community. It takes about two weeks after vaccination for antibodies that protect against flu to develop in the body. CDC recommends that people get a flu vaccine by the end of October.  Getting vaccinated later, however, can still be beneficial and vaccination should continue to be offered throughout the flu season, even into January or later.

Children who need two doses of vaccine to be protected should start the vaccination process sooner, because the two doses must be given at least four weeks apart.

Vaccination for Children

Children younger than 6 months old are the pediatric group at highest risk of serious influenza complications, but they are too young to get an influenza vaccine. The best way to protect young children is to make sure members of their household and their caregivers are vaccinated.

Influenza vaccination is recommended for all children 6 months of age and older.

Children 6 months through 8 years who have previously received 2 or more total doses of any influenza vaccine before July 1 only need one dose for 2016-17 season. The two previous doses do not need to have been given during the same season or consecutive seasons.

Children 6 months through 8 years who have previously received only 1 dose of influenza vaccine, or who have never received influenza vaccine previously, need two doses of vaccine to be fully protected for the 2016-17 season. The 2016-2017 ACIP recommendations has an algorithm to help guide clinician decision-making regarding vaccination of children 6 months through 8 years of age.

2 Dose Vaccination Instructions

The first dose should be given as soon as vaccine becomes available, and the second dose should be given at least 4 weeks after the first dose. The first dose “primes” the immune system; the second dose provides immune protection. Children who only get one dose but need two doses can have reduced or no protection from a single dose of flu vaccine. Two doses are necessary to protect these children. If your patient needs the two doses, begin the process early, so that children are protected before influenza starts circulating in your community. Make sure to remind the parent to follow up to get the child a second dose if they need one. It usually takes about two weeks after the second dose for protection to begin.

Children who require two doses of flu vaccine do not need to receive the same flu vaccine both times; live or inactivated vaccine can be used for either dose. (Within approved indications and recommendations, no preferential recommendation is made for any type or brand of licensed influenza vaccine over another.)

See Vaccine Dose Considerations for Children 6 Months through 8 Years of Age for more information.

Vaccination for Adults

Everyone 6 months of age and older are recommended to get the flu vaccine, including even the healthiest adults. Vaccination is especially important for people at high risk of serious influenza complications or people who live with or care for people at higher risk for serious complications.

Persons working in health care settings also should be vaccinated annually against influenza. Vaccination of health care professionals has been associated with reduced work absenteeism and with fewer deaths among nursing home patients.

People Who Should Not Be Vaccinated

People who have had a severe reaction to an influenza vaccination, and children younger than 6 months of age should not be vaccinated.

People who are moderately or severely ill with or without fever should usually wait until they recover before getting flu vaccine.

A history of Guillain-Barré Syndrome (GBS) within 6 weeks following receipt of influenza vaccine is a precaution for the use of influenza vaccine. Such individuals have a risk of recurrence of GBS with subsequent vaccination, and if not at high risk of severe influenza complications should generally not be vaccinated. However, while data are limited, the established benefits of influenza vaccination might outweigh the risks for many people who have a history of GBS and who also are at high risk for severe complications from influenza.

See Table 1: Influenza vaccines, contraindications and precautions in the 2016-2017 ACIP Influenza Vaccine Recommendations for more information.

Different flu vaccines are approved for use in different age groups. In addition, some vaccines are not recommended for certain groups. Factors that can determine a person’s suitability for vaccination, or vaccination with a particular vaccine, include a person’s age, health (current and past) and any allergies to flu vaccine or its components.

Vaccination of People with a History of Egg Allergy

Most influenza vaccines are produced by growing influenza virus in embryonated chicken eggs, and therefore contain trace amounts of egg protein. See Persons with a History of Egg Allergy for complete information and an algorithm to guide decision-making for vaccination of persons with egg allergy.

All vaccines should be administered in settings in which personnel and equipment for rapid recognition and treatment of anaphylaxis are available.

A previous severe allergic reaction to influenza vaccine, regardless of the component suspected to be responsible for the reaction, is a contraindication to future receipt of the vaccine.

Special Consideration Regarding Egg Allergy

People with egg allergies can receive any licensed, recommended age-appropriate influenza vaccine (IIV, RIV4, or LAIV4) that is otherwise appropriate. People who have a history of severe egg allergy (those who have had any symptom other than hives after exposure to egg) should be vaccinated in a medical setting, supervised by a health care provider who is able to recognize and manage severe allergic reactions.

Influenza Vaccines and Use of Influenza Antiviral Medications

  • Administration of inactivated influenza vaccine to persons receiving influenza antiviral drugs for treatment or chemoprophylaxis is acceptable.
  • Live-attenuated influenza vaccine should not be administered until 48 hours after cessation of influenza antiviral therapy.
  • If influenza antiviral medications are administered within 2 weeks after receipt of live-attenuated influenza vaccine, the vaccine dose should be repeated 48 or more hours after the last dose of antiviral medication.

Concurrent Administration of Influenza Vaccine With Other Vaccines

  • Inactivated vaccines do not interfere with the immune response to other inactivated vaccines or to live vaccines.
  • Inactivated or live vaccines can be administered simultaneously with live-attenuated influenza vaccine.
  • However, after administration of a live vaccine, at least 4 weeks should pass before another live vaccine is administered.

More Information

For Your Patients

VIS are information sheets produced by CDC that explain both the benefits and risks of a vaccine to vaccine recipients.

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