Critics condemn these studies, arguing that the work is not directly saving lives and is therefore not worth the risk of accidentally spreading the dangerous viruses. A group of scientists led by Yoshihiro Kawaoka from the university of Wisconsin are conducting the latest of these controversial studies. They built a virus that is only three percent different from the incredibly 1918 influenza virus, combining multiple wild bird flu strains into one strain and mutating it to make it airborne ,giving it the ability to spread through the air. Preliminary mutations were less harmful than the Spanish Influenza when tested on rodents. However, the scientists persisted in their project, and a number of mutations later , they created a more dangerous strain that spreads the same way as human flu viruses- through water droplets. While the scientists have been labeled ‘’ crazy’’ by their critics, Kawaoka says that the study is meant to demonstrate how wild bird flu strains have the potential to mutate into human flu strains and cause a pandemic similar to that of 1918. The researchers claim the swine flu vaccine from 2009should be effective on this new strain they created. Kawaoka and his colleagues assert that their work benefits public health, but with the chance that the recreated virus could be exposed to the public, opponents dispute this claim.