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Flublok Seasonal Influenza (Flu) Vaccine

Questions & Answers

On January 16, 2013, the U.S. Food and Drug Administration (FDA) announced its approval of Flublok [185 KB, 16 pages]®, a trivalent (three-component) influenza vaccine made by Protein Sciences Corporation, for the prevention of seasonal influenza in people 18 years and older. On October 7, 2016, FDA announced its approval of Flublok® Quadrivalent [182 KB, 18 pages], a quadrivalent (four-component) formulation of the vaccine intended for use in people 18 years of age and older.

What is Flublok?

Flublok® is a trivalent influenza vaccine that has been FDA approved for use in adults 18 years and older.

How does this vaccine differ from the other approved flu vaccines?

Flublok is produced differently and has a slightly shorter shelf life than most influenza vaccines.

  • Flublok does not use the influenza virus or chicken eggs in its manufacturing process. See How Influenza (Flu) Vaccines Are Made for more information.
  • Flublok has a slightly shorter shelf life than most other currently available injectable influenza vaccines; it expires 9 months from the production date. Health care providers should check the expiration date before administering Flublok.

What are the possible benefits of Flublok vaccine?

Flublok’s manufacturing process has the potential for faster startup of vaccine manufacturing, which can be useful in the event of a pandemic or vaccine supply shortage, mainly because it is not dependent on an egg supply or limited by the selection of vaccine viruses that are adapted for growth in eggs. Also, this vaccine is suitable for vaccinating people with egg allergies because it is not made using eggs.

Who can get Flublok vaccine?

Flublok is approved for use in people 18 years and older.

Who should not get Flublok vaccine?

People who are not within the FDA-approved age range (those younger than 18 years) and people with known severe allergic reactions to any component of the vaccine should not get Flublok.

Is this vaccine safe?

Clinical studies show that Flublok is safe and effective for use in people 18 years and older. Flublok meets FDA’s standards for influenza vaccines.

Are there any side effects that could occur?

The most common side effects reported after receipt of FluBlok were similar to those reported for other flu shots and include pain at the injection site, headache, fatigue, and muscle aches.

For more information see the FluBlok package insert.

Special Consideration Regarding Egg Allergy

The recommendations for vaccination of people with egg allergies have not changed since last season (2016-2017).

People with egg allergies can receive any licensed, recommended age-appropriate influenza vaccine and no longer have to be monitored for 30 minutes after receiving the vaccine. People who have severe egg allergies should be vaccinated in a medical setting and be supervised by a health care provider who is able to recognize and manage severe allergic conditions.


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