Do not administer Fluzone, Flublok, or Fluzone High-Dose to anyone with a history of a severe allergic reaction (e.g., anaphylaxis) to any component of the vaccine (including egg protein for Fluzone and Fluzone High-Dose). Fluzone and Fluzone High-Dose should not be administered to anyone who has had a severe allergic reaction after previous dose of any influenza vaccine.
Appropriate medical treatment must be immediately available to manage potential anaphylactic reactions following administration of the vaccine.
If Guillain-Barré syndrome has occurred within 6 weeks following previous influenza vaccination, the decision to give Fluzone, Flublok, or Fluzone High-Dose should be based on careful consideration of the potential benefits and risks.
Syncope (fainting) has been reported following vaccination with Fluzone, Flublok and Fluzone High-Dose. Procedures should be in place to avoid injury from fainting.
In two separate postmarketing observational studies, an increased risk of febrile seizures was observed during the first day following vaccination with standard dose trivalent (2024-2025) and quadrivalent (2023-2024) influenza vaccines in children 6 months through 4 years of age.
If Fluzone, Flublok, or Fluzone High-Dose are administered to immunocompromised persons, including those receiving immunosuppressive therapy, the expected immune response may not be attained.
Vaccination with Fluzone, Flublok, or Fluzone High-Dose may not protect all recipients.
For Fluzone, in children 6 months through 8 years of age, the most common injection-site adverse reactions were pain or tenderness and redness; the most common solicited systemic adverse reactions were irritability, drowsiness (6 months through 35 months), and myalgia (3 years through 8 years). In adults 18 through 64 years of age, the most common injection-site adverse reaction was pain; the most common solicited systemic adverse reactions were headache and myalgia. In adults over 65 years of age, the most common injection-site adverse reaction was pain; the most common solicited systemic adverse reactions were headache, myalgia, and malaise.
For Flublok, in children 9 through 17 years of age who received Flublok Quadrivalent, the most common solicited injection-site adverse reaction was pain; the most common solicited systemic adverse reactions were myalgia, headache, and malaise. In adults 18 through 64 years of age who received Flublok, the most common injection site adverse reaction was pain; the most common solicited systemic adverse reactions were headache, fatigue, and myalgia. In adults 65 years of age and older who received Flublok, the most common injection-site adverse reaction was pain; the most common solicited systemic adverse reactions were fatigue and headache.
For Fluzone High-Dose, in adults 65 years of age and older, the most common injection-site reaction was pain; the most common solicited systemic adverse reactions were myalgia, malaise, and headache.
For Fluzone, Flublok, and Fluzone High-Dose, other adverse reactions may occur.
