The Eggless Flu Vaccine: It's No Yolk

Sandra Adamson Fryhofer, MD


March 22, 2013

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Hello. I'm Dr. Sandra Fryhofer. Welcome to Medicine Matters. The topic is America's first cell culture technology-based seasonal influenza vaccine. Here is why it matters.

Traditionally, fertilized chicken eggs are used to grow flu vaccine virus strains. The process takes time -- lots of it. And from lessons learned in previous flu seasons, when things don't grow as expected, this can mean problems: vaccine production delays, vaccine shortages, and having to prioritize who receives the vaccine first.

Cell culture technology uses cultured animal mammalian cells to grow vaccine virus. The process is not totally egg-free. There is a little egg protein, but some experts describe this process as "functionally" egg-free. Cell culture technology is already used to make other vaccines, including those for polio, rubella, and hepatitis A, as well as the H1N1 vaccine distributed during the recent pandemic.

One major advantage of using this new technology is that the manufacturer says it's quicker, which could be critical for making sure that adequate quantities of vaccine are available if there is a pandemic.

The new cell culture technology-based vaccine (Flucelvax, made by Novartis) was FDA approved in November 2012 for adults aged 18 and older. It's thimerosal free and contains no other preservatives or antibiotics.

The side effects are similar to those of other flu formulations: headache, fatigue, muscle aches, injection-site reactions, and pain. There is also a warning: The tip caps of prefilled syringes may contain natural rubber latex. This could trigger an allergic reaction in patients who are latex sensitive. Studies by the manufacturer show that this new vaccine has an effectiveness of 83.8% compared with placebo for preventing the flu.