Officials with the US Food and Drug Administration (FDA) have issued an extended approval for the quadrivalent formulation of the Afluria  influenza vaccine, in individuals 6 months of age and older. The vaccine, produced by Seqirus, was first approved in the United States in August 2016 for adults 18 and older. The extended approval is also applicable to the trivalent form of the vaccine.

The quadrivalent vaccine is designed to protect against 2 influenza A strain viruses and 2 influenza B strain viruses. It is an inactivated vaccine which is available in single-dose, pre-filled syringes as well as multi-dose vials. The vaccine is available in the United States for the 2018-2019 influenza season.

Common reported adverse reactions in adults were injection site pain and myalgia and headache. In children some of the observed adverse reactions include injection site pain and redness, myalgia, malaise, fatigue, and headache.  In younger children, irritability, diarrhea and loss of appetite were also observed.

The trivalent vaccine has been developed with an egg-based technology and has been indicated for individuals 5 years of age and older. In addition to prefilled syringes and multi-dose vials, the vaccine is the only trivalent flu vaccine with a needle-free administration option, a jet injector, for individuals aged 19-64 years.

When administered via the needle-free option, the most common reactions in adults aged 18 to 64 included tenderness, swelling, pain, redness, itching and bruising. Additional adverse events included myalgia, malaise and headache.

According to documents published by the FDA, the decision to extend the approval was based on a study that compared the AFLURIA quadrivalent vaccine to a competitor quadrivalent vaccine in children aged 6 to 59 months. The study found that the vaccine was non-inferior to the competitors as measured by hemagglutination inhibition, antibody geometric mean titers, and seroconversion rates. Additionally, no notable adverse reactions of concern were observed. 

AFLURIA should not be administered to any individuals that have an allergy to any components of the vaccine including egg proteins or those who have previously suffered an allergic reaction to any influenza vaccine.

Additionally, it should be noted that immunocompromised individuals may have a diminished response to AFLURIA.

This article originally appeared on Contagion.