Almost half of the vaccines produced around the world have to be destroyed because exposure to heat alters their chemical structure and makes them less potent. Doctors are constantly trying to beat the heat by moving vaccines from refrigerator to refrigerator until they reach a clinic. And the problem gets even harder when delivering drugs to poorer parts of the world where electricity isn’t always available.
But David Kaplan and colleagues at Tufts University may have found a solution. They came up with a way to package vaccines in silk pouches so they don’t need refrigeration.
The Economist online details how it works:
“They start with silkworm cocoons-the raw material for almost all silk production. They boil the cocoons in a solution of sodium carbonate to separate a protein called fibroin, which is the one they want, from another, called sericin, which they do not. They treat the fibroin with salt, then mix it with the substance to be preserved and spread the result out as films, before freeze-drying it. The films in question consist of a fibroin matrix filled with tiny pockets a few hundred nanometres (billionths of a metre) across. These pockets contain the medicine.”
Fibroin works so well because it stabilizes the medicine so the chemicals in the vaccine stay in the right folded shape regardless of the temperature outside.
The technique was tested on the (MMR) measles, mumps and rubella vaccine and “was still about 85% potent after six months, regardless of temperature,” The Economist online reports.
If this this new method of vaccine storage works in human trials, it could save billions of dollars and could bring much needed drugs to some of the poorest countries in the world.
