Researchers Work To Create Possible Swine Flu Vaccine
Federal officials are looking into a possible swine flu vaccine and say it is important to be ready for a quick production of millions of doses, The New York Times reported.
Such vaccines are created from flu virus “seed stock” “” a form of the virus that will grow rapidly in eggs so that drug companies can use it to make vaccine doses.
However, health officials have not yet decided whether to call for a swine flu vaccine – and since the virus is new, some people may need two shots to build immunity.
Considering the vaccine would probably be separate from seasonal flu vaccine, a total of three shots might be recommended for certain people who are at greater risk.
Dr. Doris Bucher, an associate professor of microbiology and immunology at New York Medical College, runs a laboratory in Westchester County that is highly regarded for its skill at turning flu viruses into “seed stock”.
Experts say creating the seed stock is an essential first step for any vaccine and the Centers for Disease Control and Prevention have sent samples of the new strain to about 10 other government and academic laboratories in this country as well as Australia, Britain, Hungary and Russia.
Dr. Bucher’s laboratory has provided seed stock for one of the virus strains included in the seasonal flu vaccine for the past five years.
“Our job is to make it grow really well. We’re good at this,” she said.
Bucher said one of her group’s strengths has been in developing a “high-yield donor,” which means an influenza virus that grows well in eggs and that, when injected into eggs along with a new strain like H1N1, will trade some of its genes with the newer strain.
This results in an array of new viruses and the researchers can sort through it to pick ones that will grow well in eggs yet retain the new strain’s traits on the outside.
This allows the vaccine to spark immunity when injected into people.
On April 28th, Bucher received a vial containing millions of swine flu viruses in a milliliter of fluid that was packed with dry ice in a foam box labeled, “infectious substance affecting humans.”
A cotton swab rubbed in the nose and throat of a child in California who received one of the first diagnoses of the flu in this country was cited as the original source the viruses had been grown from.
Dr. Bucher’s team decided the first task was to make more of the virus by injecting it into fertilized eggs from leghorn hens.
In order to create the seed stock, members of the team amplify virus genes, cut them up with enzymes and analyze their origins. Next, the researchers candle eggs, mark the shells with a pencil, and shoot them full of swine flu viruses using a drill.
The entire process involves repeated rounds of injecting the two types of virus into eggs, and sorting and purifying what grows. It takes about 42 hours for each round of virus to grow.
Bucher’s team will attempt to create a uniform seed stock from a single virus that will produce 80 vials, each containing millions of viruses. Bucher said she expected to ship out those 80 vials by May 25th to drug companies, the C.D.C. and the Food and Drug Administration.
Rene Devis, a research associate, said while the team was usually not alarmed when working with flu viruses, he admitted he did feel a bit concerned at first.
But Devis said his attitude was: “You don’t think of yourself.” He added that they must do what they have to do, especially if it can help save a life.
Bucher’s team had recently finished a seed stock for the next seasonal flu vaccine and had started work on other projects before the swine flu outbreak gripped the country.
She said they are now back to focusing on flu viruses, and working so hard she fears they will burn out.
And should health authorities decide there is no need to make a vaccine after all, Bucher said they would simply put it in the freezer.
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