Banana vaccines.

Getting vaccinated against diseases could soon be as easy as eating a banana Sound far-fetched? Researchers at the Boyce Thompson Institute for Plant Research at Cornell University don't think so. They are creating bananas that, when eaten, could prevent people from getting diseases like hepatitis B, cholera, and diarrhea. More than 3 million children in developing countries like Mexico die from these diseases every year.

The diseases are caused by viruses, tiny particles of genetic material wrapped in protein. When a virus attacks a cell, it injects its genetic material, which takes over and can kill the cell.

Fortunately, your disease-fighting immune system learn to recognize many viruses' protein coats and make antibodies to fight them off. That's where vaccines come in. Giving people small doses of a virus (not enough to make them sick) can prime the immune system to make antibodies.

But the vaccines most kids get in the United States are expensive -- $50 to $100 per child. Bananas containing vaccines would be much cheaper and easier to deliver to children throughout the world.

One vaccine-producing banana plant could grow more than 100 pounds of bananas! The bananas will be picked, peeled, and mashed into a puree like baby food. A spoonful of the stuff once or twice a year will prevent diseases. It would cost only a couple of cents to make each vaccine.

To make the banana vaccines, scientists inject an altered form of the virus into a banana sapling. The virus' genetic material becomes a permanent part of the plant's cells. As the plant grows, its cells produce the virus proteins, but not the infectious part of the virus.

After eating a bite of banana -- full of the virus proteins -- the person's immune system builds up antibodies and is ready to fight off the real disease.

If all goes well, a few years from now edible vaccines will be ready to peel around the world.