It is the first time scientists have managed to make an edible vaccine for a virus. The Norwalk virus vaccine was produced in collaboration with Axis Genetics, the British plant biotechnology company that went out of business last autumn because antipathy to genetically modified foods had made investors wary of putting money into the sector. The administrators sold Axis's assets and intellectual property to Dow, the US chemical and agricultural sciences company, which stands to benefit if the research is commercialised. In 1998, the same scientists successfully tested an edible vaccine against E. coli bacteria, which cause a more dangerous form of diarrhoea, but more extensive clinical trials have been held up by concern about the possible risks. Because the Norwalk virus is potentially lethal only to infants and people with impaired immune systems, Professor Arntzen believes further trials of the viral vaccine can be organised quickly.
Edible vaccines hold great appeal, because food is almost universally preferred to needles.
They are especially significant, however, for the developing world where immunisation costs are a forbidding barrier in fighting disease. Edible vaccines would, in theory, be cheaper than the traditional alternative because they would not have to undergo expensive purification and refrigeration. If the food is grown locally, it would also save on shipping costs. Potatoes are not the ideal vehicle for edible vaccines, because they are usually cooked before being consumed and are not popular in many developing countries. The Cornell crop loses its medicinal value when heated.