Microinjection Flu Vaccine Product Approved by FDA

Intradermal Needle Is One-tenth Size of Those Used in Intramuscular Products

May 12, 2011 04:55 pm David Mitchell

Family physicians soon may have a new weapon in their armamentarium to prevent influenza.

Pharmaceutical manufacturer Sanofi Pasteur said in a May 10 news release(sanofipasteurus.mediaroom.com) that the FDA has approved the company's license application for Fluzone Intradermal, making it the first influenza vaccine that uses a microinjection system to be licensed in the United States.

David Greenberg, M.D., senior director of scientific and medical affairs for Sanofi Pasteur, said in a video(multivu.prnewswire.com) posted on the company's website that the 1.5-millimeter needle used with Fluzone Intradermal is 90 percent shorter than needles used for intramuscularly administered vaccines.

Fluzone Intradermal -- which ships as a single-dose, preservative-free, prefilled syringe -- is indicated for use in patients ages 18-64 years.

"This provides a new option for people in this age group, who traditionally have a low rate of immunization," Greenberg said.

The CDC's Advisory Committee on Immunization Practices, or ACIP; the American College of Obstetricians and Gynecologists; the American College of Physicians; and the AAFP recommend(4 page PDF) annual vaccination against influenza for all people ages 6 months and older in whom the vaccine is not contraindicated.

However, only 41 percent of Americans ages 6 months and older received seasonal flu vaccine during the 2009-10 influenza season, according to the CDC(www.cdc.gov). The rates were higher -- 38 percent -- for adults ages 18-49 who were at high risk for complications from the flu(www.cdc.gov), but only 28 percent of age-matched individuals who were not in a high-risk group received the vaccine. Forty-five percent of adults 50-64 were immunized against the flu.

"Alternative methods for getting vaccines into people is a very good thing," Jonathan Temte, M.D., Ph.D., a member of the ACIP and a professor in the department of family medicine at the University of Wisconsin School of Medicine and Public Health, Madison, told AAFP News Now. "Some people will find those alternative methods more acceptable than intramuscular injections."

According to the CDC's National Center for Immunization and Respiratory Diseases, the ACIP is scheduled to discuss the new vaccine product at its June 22-23 meeting. The agenda for that meeting(www.cdc.gov) is expected to be posted on the CDC website by May 16.

Fluzone Intradermal vaccine contains 9 mcg of hemagglutinin per strain of influenza in a 0.1 mL dose, compared to 15 mcg of hemagglutinin per strain of influenza in a 0.5 mL dose of the original version of Fluzone.

According to Sanofi Pasteur's news release, Fluzone Intradermal vaccine provided an immune response similar to that seen with intramuscular Fluzone in a clinical trial that involved more than 4,000 participants.

Greenberg said the clinical trials also showed the vaccine to be safe. He said the incidence of systemic reactions, such as fever and headache, with Fluzone Intradermal were similar to those encountered by patients who received Fluzone vaccine administered via the intramuscular route. The incidence of local reactions, such as redness, were higher with Fluzone Intradermal, which Greenberg said was expected with a vaccine that deposits antigens into the dermal layer of the skin.

A fact sheet(multivu.prnewswire.com) produced by the drugmaker says that the new product will be available for the 2011-12 flu season.

Sanofi Pasteur spokesperson Donna Cary said in an interview with AAFP News Now that the company expects to start taking orders for Fluzone Intradermal by early June. The vaccine will carry a list price of $15.50 per dose, compared to $10-$12 per dose for various intramuscular presentations of Fluzone and $25 per dose for Fluzone High-Dose, the version of the vaccine designed specifically for people 65 years and older.

Sanofi already has licensed microinjection influenza vaccines in more than 40 countries, and Cary said the company will look at applying its microinjection technology to other vaccines, but none are yet in clinical trials