Faster flu vaccine looms

The race is on to develop flu vaccines without the requisite lag time to produce the millions of doses needed to protect the population, and a Rockville company is at the forefront.

As scientists worldwide rush to produce and distribute a vaccine for the H1N1 swine flu strain in time for the flu season, U.S. companies are working on a new process that uses genetic engineering and cell cultures instead of chicken eggs to “incubate” the virus and create the vaccine.

Novavax Inc. of Rockville and other companies have had a scientific breakthrough with the first successful animal testing of an H1N1 vaccine developed using that process in the less than four weeks after the U.S. Centers for Disease Control and Prevention provided the genetic sequence of the virus. That’s a huge improvement over conventional methods, which can take five to six months.

These promising new vaccines will not factor into this year’s flu season or the threat of a major H1N1 epidemic, as they require Food and Drug Administration approval and years of human trials.

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At least two other American companies also are using genetic engineering for similar work, said Dr. Gary J. Nabel, head of the Vaccine Research Center at the National Institute of Allergy and Infectious Diseases (NIAID), part of the Bethesda-based National Institutes of Health. They are Protein Sciences Corporation Inc. of Meriden, Conn., and VaxInnate Corp. of Cranbury, N.J.

“This next generation relies on a more molecular biological approach. Instead of growing the virus itself in eggs, you grow them in cell cultures that are much more manageable. You can scale them up more rapidly. You grow them and keep them in storage and you don’t have to depend on fresh eggs coming in,” said Dr. Anthony Fauci, NIAID director.

The new methods use bacteria or insect cells to generate a vaccine, Dr. Fauci said. All three companies use these types of cell cultures to create an artificial protein form that produces the protective vaccine.

The 50-year-old conventional method - being used to create a vaccine for the new swine flu strain -requires the use of use of millions of specially prepared live chicken eggs to be injected with a virus strain to eventually produce the vaccine. At least one or two eggs are needed for a single dose of vaccine.

VaxInnate Chief Executive Officer Alan Shaw said that while the newer methods can complete the process of creating a vaccine within a month, getting one to market is a considerably longer process because of testing requirements.

“Creation of a bacterial production strain takes only three weeks, and two weeks to manufacture about 200 million doses of vaccine in bulk,” he said. But quality-control testing, which follows, can take several more weeks.

Another advantage of the new process, though yet to be proved in human clinical trials, is its ability to more rapidly adapt in case of a shift in the flu strain, Dr. Nabel said.

“It’s a more facile technology and good - in a sense it is safer - because it is one more step removed from the normal virus.” The egg method employs a real virus, compared with an artificially grown one - and, for that reason, people with allergies to eggs normally are advised not to take the vaccination.

Novavax used what Dr. Nabel called “a number of molecular tricks” to make a vaccine out of what the company’s press release said were viruslike particles coated with the same proteins that are on the outside of the virus.

These so-called decoys attach to immune cells that mistake the particles for viruses and stimulate an immune response. Two doses of the Novavax vaccine were shown to protect ferrets, the animal that most resembles humans when injected with influenza.

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