Flu Shots: What’s In the Seasonal Influenza Vaccine?

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FluZone is one of the brand of flu vaccines this year. Photo by: CDC

FluZone is one brand of flu vaccines available this year. Photo by: CDC

The 2012-2013 influenza epidemic continues across the United States. The Centers for Disease Control and Prevention (CDC) reports that for the week ending in January 12, 2013, 48 states have reported widespread flu activity and 29 children (18 years and younger) have died from the flu. The CDC is recommending that everyone six months and older receive the flu shot. However, some people are skeptical when it comes to what is in the ingredients. Let’s take a look at the Fluzone shot to see what’s in there.

What’s in the Flu Shot?

The flu shot contains three types of dead flu viruses: influenza A (H1N1), influenza A (H3N2), and influenza B, according to the U.S. Food and Drug Administration. These viruses are selected each year by experts from the FDA, CDC, and the World Health Organization (WHO) who study flu patterns and predict which viruses will be the most ‘popular’ so to speak. It’s an educated guess at best, but during the first week of January 2013, 91 percent of the influenza viruses that have been tested were the same viruses that are in the vaccine.

Is the Flu Shot Safe? What About Mercury?

Preservatives in the flu shot are needed to prevent contamination, according to the CDC. The preservative that we find in multi-dose flu shots is thimerosal (ethylmercury). Vaccine labs add Thimerosal to multidose vaccines because each time a new needle is inserted into the vial, there is a chance of introducing microbes into the vaccine and contaminating it. The amount of thimerosal in the 0.5mL dose of FluZone is 25mcg.

Mercury in Flu Vaccines: The amount of a chemical a person can have in their bodies without having adverse health affects is called a reference dose. The reference dose for methylmercury is 0.1 µg/kg body weight/day, or .1 microgram per kilogram of body weight per day. A 40 lb child is about 18 kilograms, which makes the safe dose about 1.8 micrograms – many times less than the dose in a flu shot. Thimerosal, however, isn’t methylmercury, it’s ethylmercury – so what’s the safe dose? The research on safe doses of ethylmercury is extremely sparse, so the dosage is generally based on the more toxic methylmercury.

Due to the controversy over safety, childhood vaccines, other than the flu shot, no longer contain Thimerosal in the United States. If you’re concerned about mercury in your child’s vaccine, you can ask for the thimerosal-free flu shot.

Flu Vaccine: What Else is In There?

The flu shot also contains the following ingredients: sodium phosphate – buffered isotonic sodium chloride solution, formaldehyde, octylphenol ethoxylate, and gelatin, according to the FDA. The influenza virus is grown in chicken eggs and scientists collect the virus and inactivate it by using formaldehyde. They then purify the influenza virus and suspend it in a sugar solution before splitting it with oxtylphenol ethoxylate. After splitting, the scientists purify the virus once more, then suspend it in a salt solution (sodium phosphate – buffered isotonic sodium chloride) and use gelatin to help keep the viruses stable and potent during storage.

Click to Read Page Two: Formaldehyde in Vaccines

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© Copyright 2013 Janelle Vaesa, MPH, All rights Reserved. Written For: Decoded Science
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