As of right now, the bird flu can only be contracted from bird to human. Humans do not have immunity against the bird flu virus because of the fact that it is an animal virus and we are not capable of passing the bird flu virus on to other humans. The only way it would be possible for us as human to pass the bird flu virus onto others is if the virus happened to mutate (which is very possible and precautions are being taken) and there for become spreadable from person to person. In the case that the virus does mutate and become spreadable amongst humans, its important to realize that the most highly populated areas would take a large hit to this virus causing illness and possibly even death. In march of 2007, the FDA (Food and Drug Administration) approved a vaccine which is said to be used if a bird flu pandemic takes place. The vaccine would be most useful in highly populated areas as highly populated areas for a faster spread rate of viruses such as these. With this vaccine, it may be possible to prevent a world wide pandemic of the bird flu from occurring, and it would be important for highly populated areas to be vaccinated against this bird flu virus to prevent the spread and contraction of the bird flu. As of right now the bird flu has not mutated, and it still cannot be passed from person to person but if it did, we would be prepared.