FDA OKs Flu Shot With Smaller Needle

New Needle Is 90% Shorter Than Traditional Needle

By Bill Hendrick
WebMD Health News

Reviewed By Laura J. Martin, MD

May 12, 2011 -- The FDA has approved the first flu shot to be injected with a tiny needle into a skin layer called the dermis rather than into muscle.

The new needle is expected to be available for adults for the 2011-2012 flu season.

The French drugmaker Sanofi Pasteur says the company's Fluzone Intradermal vaccine will be administered with a needle less than one-tenth of an inch long. That's 90% shorter than those used now in the U.S., and therefore won't need to be inserted as deeply.

In general, current influenza shots are injected deep into muscle tissue with a needle that can be 1 to 1.5 inches long.

Sanofi Pasteur says in a news release that its new product has a needle that is attached to a prefilled syringe that holds a smaller amount of flu vaccine.

The smaller amount of Fluzone is all that is needed because the skin layer under the surface, the dermis, has a high concentration of dendritic cells, which are key to generating an immune response.

New Tool to Increase Vaccine Rates

According to Sanofi Pasteur's U.S. affiliate, patients have indicated they prefer shorter, slimmer needles of the Fluzone Intradermal vaccine. The short needles already are used in Europe, Australia, and Canada.

Oliver Charmeil, CEO of Sanofi Pasteur, the vaccines division of Sanofi-Aventis Group, says the new product is likely to increase flu vaccination rates in the U.S.

Flu and its complications kill thousands of people in the U.S. every year, yet many adults don't get the flu vaccine. The CDC says on its web site that flu deaths vary from a low of about 3,000 to about 49,000 yearly.

Short Needle vs. Traditional Needle

The FDA's approval was based on clinical trial data of 4,276 adults who were randomly assigned to receive Fluzone via intradermal (dermal layer of skin) or intramuscular routes. People in the intradermal group had a similar immunologic response as people who received intramuscular injections, Sanofi Pasteur says.

People in the intradermal group experienced more frequent injection site reactions, except pain, which was similar in both groups. Adverse reactions included redness, swelling, pain, itching, headache, muscle ache, and malaise.

The vaccine, the company says, may trigger anaphylaxis in patients who are hypersensitive to any of its components.

The new formulation is to be used in adults aged 18 to 64.

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SOURCES: News release, Sanofi Pasteur.CDC web site: "Seasonal Influenza." ©2011 WebMD, LLC. All Rights Reserved.

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