Currently there have been no successful edible vaccines in clinical trials, but scientists have developed several candidates for edible bacterial, viral and parasitic vaccines. An interesting example is the development of the plant-derived vaccine against Bacillus anthracis, the bacteria that causes anthrax. An antigen was produced in tobacco plant leaves and injected into mice9. With the vaccine, the mice survived a lethal infection of anthrax. This vaccine, however successful, had to be injected to induce a strong enough immune response to fight against future anthrax infection. With the real goal of plant-derived vaccine research being that the vaccines are ingested rather than injected, this example illustrates that much more research is needed before any success occurs.