Vaccine strains are grown in nearly 300 million live chicken eggs. The virus is then harvested, inactivated, purified, mixed, and tested before being approved.
How is Seasonal Flu Vaccine Made?
- The entire process, from collecting, injecting and incubating millions of specially produced eggs through the safety tests on the vaccine, takes five to eight months. This means that health officials must decide one year in advance which flu viruses to use in its vaccines and how many batches of vaccine to purchase.
- Even with robotic assistance, “working with eggs is tedious,” says Samuel L. Katz of the Duke University School of Medicine, a member of the vaccine advisory committee for the U.S. Food and Drug Administration.
- Because of the nature of flu vaccine production, vaccine companies must place their egg orders 5-8 months in advance before they begin producing vaccines.
- This process consumes hundreds of millions of eggs (270 million or more for the United States alone) to produce a sufficient supply of vaccine for the United States.
- “The egg method isn't very flexible if you need to rapidly ramp up vaccine supply,” says Jonathan Seals, director of Process Development at ID Biomedical Corporation of Northborough, MA. “Vaccine manufacturers need to arrange for egg supplies months in advance - and you can't tell a chicken to lay more eggs.”
- Modern cell culture-based production methods are now being researched, but are years away from completion. Today, influenza vaccines are prepared in a modernized version of original methods.
Projected vaccine production by percentage, 2011-2012 season
Sources: National Institutes of Health at http://www.niaid.nih.gov/TOPICS/FLU/UNDERSTANDINGFLU/Pages/seasonalVaccine.aspx, the Centers for Disease Control and Prevention at http://www.cdc.gov/flu/flu_vaccine_updates.htm
Graph - As reported by manufacturers at the CDC-AMA National Influenza Summit, May 2011
For more information on how the manufacturing and distribution process works, please see our interactive graphic. >>
Did You Know?
Nearly 136 million doses of seasonal flu vaccine were produced for the 2008-2009 influenza season.
Flu Vaccine Production Process
Graphic content derived from January 2006 CDC/AMA Flu Summit presentation
