Technology Review: Swine Flu Genome Hints at Milder Virus

People exposed to the 1957 flu pandemic may have some immunity to the current H1N1.

Technology Review: Blogs: TR Editors' blog: Swine Flu Genome Hints at Milder Virus:

"Ralph Tripp, an influenza expert at the University of Georgia, said that his early analysis of the virus' protein-making instructions suggested that people exposed to the 1957 flu pandemic--which killed up to 2 million people worldwide--may have some immunity to the new strain. That could explain why older people have been spared in Mexico, where the swine flu has been most deadly."

Secrets of the Dead: Killer Flu suggested that the distribution of deaths by age in the 1918 pandemic hinted at a prior outbreak, about fifty years earlier.