"A hallmark of pandemic flu throughout history, including the 2009 H1N1pandemic, has been its ability to make healthy young and middle-aged adults seriously ill and even kill this population in disproportionate numbers. Researchers now provide a possible explanation for this alarming phenomenon of pandemic flu. The study's findings suggest people are made critically ill, or even killed, by their own immune response."
"Scientists created a highly contagious and lethal strain of H5N1 influenza by adding just a single gene from H3N2, a common human flu strain. It's just this sort of nightmare strain that people have feared could evolve naturally. It hasn't yet, but this shows that it could."