In the last few years, the bird flu virus has been in the news a lot. There were fears in the world medical community that a pandemic might overrun the planet. Authorities in many countries put safeguards in place to prevent the spread from one continent to another. Wild migrating bird flocks were monitored carefully. In European countries there were worries about running short of vaccine if an epidemic hit, because the vaccine has a very short shelf life.
Then a PhD student at the University of Groningen in the Netherlands, Jean-Pierre Amorij, announced at the end of 2007 all that could change. In his thesis he describes a way of storing flu vaccine in powder form. It can then be stored for at least a year—more than enough time to build up stocks.
SUGARS ARE THE SECRET
During his four-year program, Amorij examined all kinds of methods for long-term storage of the flu vaccine. The answer came in what is known as freeze-drying. A protein molecule, such as a vaccine, can be frozen between millions of sugar molecules. These molecules bunch together like miniscule balls around the vaccine, protecting it, so it can be stored stably in dried form. He used special sugars for the process, inulin and trehalose and searched for 18 months to find the freeze-drying process that was exactly right.
“The biggest problem was choosing the right freezing speed and the right sugar,” says Amorij. But he managed it, with the results looking like sugar used for frosting cakes.
ONE BENEFIT? EASE OF APPLICATION
Freeze-dried flu vaccine not only has a longer shelf-life, it is also easier to use. The powdered vaccine can be swallowed or inhaled, so there will be no more need for injection needles. You don’t need to have medical personnel involved and distribution can be a lot faster, making it possible to immunize large groups of people in a short time. “Inhaling the vaccine is by far the most effective …” Amorij says. “The immune reaction was even more powerful than with an injection.” According to him, the powder is particularly suited to inhalation. It is very light and stays suspended so it can penetrate deep into the lungs. That makes absorption even more efficient.
WHEN WILL IT BE AVAILABLE?
To date only laboratory tests have been run. “So far we’ve tested it only on mice. The tests on people still have to take place. If everything goes well, then that could happen within five years. If there are a few setbacks, it could take 10 years. One thing is certain, though, it’s on its way.”
Amorij was awarded his PhD on January 4, 2008.
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