News Health & Medicine H1N1 virus lacks Spanish flu’s killer protein Molecule responsible for extent of 1918 pandemic is missing in today’s swine variant By Tina Hesman Saey June 15, 2010 at 11:22 am - More than 2 years ago Share this:Share Share via email (Opens in new window) Email Click to share on Facebook (Opens in new window) Facebook Click to share on Reddit (Opens in new window) Reddit Click to share on X (Opens in new window) X Click to print (Opens in new window) Print BOSTON — The H1N1 swine flu just doesn’t have what it takes to be a real killer, a new study of the 1918 Spanish flu suggests. Scientists have been studying the 1918 Spanish flu virus to find out what made it so deadly.