Vaccine maker gets swine flu inoculation starter virus

:56 PM EDT, May 27, 2009

Sanofi Pasteur, the world's largest vaccine manufacturer, announced Wednesday that it has received the seed virus - the starter material - required to produce inoculations against swine flu, which now has affected people in 48 countries.

The company, based in France, is gearing up to manufacture millions of doses, but first must learn how the virus responds under manufacturing conditions before full-scale production can begin, said Donna Cary, spokeswoman at the company's division in Swiftwater, Pa.

Having the seed virus in hand, Cary said, means the company can start a development process called "passaging," which is expected to yield viral material called the "working seed." Passaging acclimates the virus to grow under manufacturing conditions.

The passaging process, according to Cary, is expected to take about two weeks. During the process the seed virus is tested in fertilized hens' eggs, the medium in which flu shots are developed. Industrial production, Cary said, will begin after the U.S. Food and Drug Administration determines the working seed has remained identical to the starter virus.

• Unlike other countries, the United States requires a clinical trial, to determine vaccine safety, appropriate dosage and whether a so-called adjuvant is needed. An adjuvant is an immune system booster that would allow the vaccine to be delivered at a lower dose, Cary said. If the working seed is ready in June, she estimates, clinical trials can probably begin in August. Completed vaccine could be ready before the end of the year.
  
  "We'll probably continue to produce while the clinical trials are under way because we already have the orders for the vaccine. Once the clinical trials are done, then [the dose] can be formulated based on findings from the clinical trials," Cary said.
  
  "Right now, what we're preparing is a monovalent vaccine," Cary said of a vaccine that is aimed at against a single flu strain. The annual seasonal vaccine is trivalent, targeted against three viral strains: two subtypes of influenza A and one B strain.
  
  Addressing the importance of vaccination last week, Dr. Susan V. Donelan, an infectious disease specialist at Stony Brook University Medical Center, said having a vaccine against the novel H1N1 swine flu virus is important. Vaccination, she said, helps lower the number of deaths that occur annually as a direct result of circulating seasonal flu. "Every year during ordinary seasonal flu about 35,000 people die. Now picture a new flu and no vaccine - the at-risk population is everybody," Donelan said