One of the biggest problems with vaccines is that they usually need refrigeration. PATH has long worked on this problem, called the cold chain, on a variety of fronts.
Luke Timmerman of Xconomy has a good description of this latest project and why it matters:
One of the big ideas PATH is pursuing to make vaccines more useful just got a strong vote of confidence. PATH is announcing today it has secured a $5.2 million contract from the U.S. government to develop flu vaccines that can remain effective for years when they are stashed away in a stockpile, in case officials ever need it to perform mass vaccinations during a global flu pandemic.