Do you know your flu shots?

Influenza Vaccines are Here!

There are 3 types of flu vaccines: inactivated influenza vaccine (IIV), live attenuated (LAIV), and recombinant (RIV). ACIP recommends giving the flu vaccine to anyone over 6mo of age. High-dose IIV is indicated only in patients ≥65yo.

Influenza vaccines are not all licensed for the same age groups. ACIP does not state a preference for one influenza vaccine over another for people for whom more than one vaccine is recommended and appropriate (see discussion below). The Immunization Action Coalition (IAC) has a handout that summarizes each of the products available for the current flu season

1 or 2 doses?

Give 2 doses (minimum 4 weeks apart) to kids aged 6mo-8yo who are receiving the flu vaccine for the first time. Otherwise, there is no reason to ever give more than 1 flu vaccine in a season.

Fun fact: Multiple studies have established that maternal vaccination can prevent influenza in infants (through transplacentally transferred antibodies) up to 6 months after birth!

High risk?

There are multiple groups considered to be high risk for complications from influenza infection:

  • Patients aged 6-59mo and ≥50yo
  • Immunocompromised status
  • Multiple forms of chronic disease (cardiovascular, pulmonary, hepatic, renal, hematologic, endocrine/metabolic, neurologic)
  • Pregnancy
  • Patients aged 6mo-18yo taking ASA
  • Residents of long-term care facilities
  • BMI ≥40

It is also a priority to vaccinate close contacts of people at high risk, especially age extremes and immunocompromised status.

Contraindications / Precautions?

There are 1 contraindication and 2 precautions common to all flu vaccines (note that there are many more for LAIV, listed in the next section):

  • Contraindication: H/o severe allergic reaction to the flu vaccine or any of its components
  • Precautions:
    • Moderate/severe acute illness with or without fever
    • H/o GBS within 6wk of a prior flu vaccine


LAIV, which is intranasal (aka FluMist), can be given to patients aged 2-49yo, but there are multiple contraindications and precautions to consider (in addition to the general contraindications/precautions listed above):

  • Contraindications:
    • Pregnancy
    • Immunocompromised status or asplenia
    • Close contact with someone who is severely immunocompromised
    • Patients aged 2-18yo taking ASA
    • Recent use of oseltamivir (or similar antiviral drug)
    • Patients aged 2-4yo with h/o asthma or documented h/o wheezing
    • CSF leak or cochlear implant
  • Precautions (IIV preferred for both):
    • Patients ≥5yo with asthma
    • Multiple forms of chronic disease (heart, lung, liver, kidney, blood, endocrine, metabolic, and neurologic)

Egg allergy?

IIV and LAIV are cultured on fluid from chicken embryos. As a result, there is a theoretical risk of inducing an allergic reaction when administering the flu vaccine to patients with egg allergy; however, no serious reactions have been reported. ACIP notes that flu vaccines should be administered to these patients under supervision of a healthcare provider able to manage and recognize severe allergic reactions. The AAP and American Academy of Allergy, Asthma, and Immunology (AAAAI) say there is no need to ask patients about egg allergy or take any special precautions in patients with known egg allergy.

More questions?

Ask our own vaccine expert and ACIP member, Dr. Cineas (aka Vaccineas), or check out this FAQ from the IAC!

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