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Novel Influenza Vaccine Approved

Darrell Hulisz, RPh, PharmD
Jessica Alflen, D

February 5, 2013

Influenza remains an important communicable disease in the US, resulting in over 200,000 hospitalizations annually. The number of influenza cases is on the rise this season, with some areas seeing very high numbers, despite aggressive influenza vaccination efforts. On January 16, 2013, the FDA approved a novel influenza vaccine, marketed as Flublok®. This flu shot will allow a subset of individuals to be vaccinated that were previously unable to receive flu shots, namely those allergic to eggs.

Flublok® is a trivalent influenza vaccine made using an insect virus (baculovirus) expression system and recombinant DNA technology. The vaccine does not use eggs or the influenza virus in its production. Thus, it is safe for patients with egg-related allergies and it can be made more rapidly in the event of a pandemic. Additionally, Flublok® does not contain antibiotics, adjuvants or preservatives, such as thimerosal.

It is approved for the prevention of seasonal influenza in people 18 through 49 years of age. Safety and effectiveness have not been established in pregnant women, nursing mothers, children or adults 50 years of age and older. Clinical trials with Flublok® suggest that it is more effective at generating protective antibody titers against influenza in elderly and immune-compromised individuals compared to licensed vaccines.

Flublok® contains three, full-length, recombinant HA proteins to help protect against two influenza virus A strains, H1N1 and H3N2, and one influenza virus B strain. It is formulated to contain three times the active ingredients in widely available influenza vaccines. According to the FDA, the vaccine was found to be 44.6% effective against all strains of influenza. Common side effects included muscle aches, headache, fatigue and pain at the injection site. A small quantity of the vaccine is expected to be available by this winter. However, it will be widely available for the 2013-2014 influenza season.