What's in a flu shot?

NEW HANOVER COUNTY (WECT) – Myths about flu shots are contagious during this time of year, so WECT.com researched what exactly is in a flu shot.

Before you panic, yes, traces of formaldehyde and detergents can be found in flu shots. That's because they're both used in the process of creating a flu vaccine.

What's in your flu shot will depend on the manufacturer. For this example, WECT.com chose Sanofi-Pastuer's FluZone vaccine because the New Hanover County Health Department carries it.

Dr. David Greenberg is Senior Director of Science and Medical Affairs for Sanofi-Pasteur, which is the largest company in the world that focuses on human vaccines.

The influenza virus is grown in the egg whites of chicken egg, but then killed with formaldehyde, according to Dr. Greenberg. He said formaldehyde is not intentionally added, but a small trace of it could appear in a dose.

Years ago you might receive an entire virus in a single dose, but not anymore. Dr. Greenberg said the company breaks down the whole virus into smaller pieces.

Those pieces actually do more, because they offer exposed protein which stimulates your immune system.

Detergents are needed for the breakdown process. You might think of detergents as a cleaner, but Dr. Greenberg said the smaller amount of dead influenza is then purified before filling a syringe.

Dr. Greenberg also refutes any myths about people catching the flu from their flu shot. A portion of a dead virus simply isn't enough, according to Dr. Greenberg. He said people can feel different from day to day all the time during flu season. The slightest change in weather, routine or diet could be a simple explanation.

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