One of the other things is the very high fatality rate from H5N1 generally has come, previous to this current strain, from primary cases with very intensive exp

One of the other things is the very high fatality rate from H5N1 generally has come, previous to this current strain, from primary cases with very intensive exposure to the avian-adapted strain, which is much more fond of receptors in the lower respiratory tract. Those types of cases for many infectious diseases (i.e. MERS) are much more lethal than subsequent human-to-human infections.