Flu Vaccine Grown in Insect Cells Called a Promising Alternative

Early trial finds the approach produced safe and effective inoculations, study says.

By Serena Gordon
HealthDay Reporter
Tuesday, April 10, 2007; 12:00 AM

Copyright © 2007 ScoutNews, LLC. All rights reserved.

TUESDAY, April 10 (HealthDay News) -- The latest buzz in flu vaccine development could be the use of an insect-cell-based vaccine, rather than egg-based immunizations, to speed up production and maintain effectiveness, particularly in the case of a pandemic flu outbreak.

An experimental vaccine was tested in about 300 people and produced an immune response strong enough to fight off the flu, while only causing minimal side effects, such as pain at the site of the injection, researchers reported in the April 11 issue of the Journal of the American Medical Association.

"All currently licensed influenza vaccines in the United States are produced in embryonic hen's eggs," wrote the study authors, from Cincinnati Children's Hospital Medical Center, the University of Rochester and the University of Virginia. The authors also pointed out that "eggs require specialized manufacturing facilities and could be difficult to scale up rapidly in response to an emerging need such as a pandemic."

Each year, as many as 20 percent of the American population gets infected with the flu virus, resulting in about 200,000 hospitalizations annually. More than 35,000 Americans die each year from complications of the flu, according to the U.S. Centers for Disease Control and Prevention. The influenza vaccine is the only known way to try to prevent the flu.

But, as the authors pointed out, developing a vaccine from eggs can be difficult. Millions and millions of eggs have to be kept at the right temperature, and flu viruses don't always grow well in eggs. Also, people who are allergic to eggs can't use egg-based vaccines.

But, one of the biggest difficulties stemming from the use of egg-based vaccines is the time it takes to manufacture these immunizations.

"It takes about six to nine months to make a batch, so you have to anticipate what will be the emerging flu strains almost a year ahead of time," explained Dr. Marc Siegel, an internist at New York University Medical Center and author of Bird Flu: Everything You Need to Know About the Next Pandemic.