One of the biggest issues in the world of epidemiology right now is the avian flu. This deadly flu started in Southeastern Asia and is thought to cause the next a pandemic, such as AIDS or polio (which has now almost extinguished). Scientists are rushing to make a vaccine for this avian-flu bug that can be transferred to people. We are still not sure if it will work. You might be able to recall the big flu vaccine shortage earlier this year. Such problems happen because it takes way longer for the vaccines to be made than it does for a certain virus to spread. According to the Wall street journal, when the right vaccine is discovered it will approximately six months to make enough vaccine to supply 10% to 20% of the US and Europe. Most of the countries in the world are not yet addressing this HUGE issue yet; the US has bought stockpiles of the H5N1 vaccine, but who is to say that the vaccine will work if it is stored. This Avian flu is especially dangerous because it can mutate to be transferred from person to person. If such a mutation was to happen (not unlikely), it could spread around the world in six months and we would not have immunity to it.