By Richard Knox
Ever since 1918, the world has wondered why a novel flu virus touched off an explosive pandemic that killed as many as 50 million people – most of them healthy young adults — and whether it could happen again.
Flu researchers today report some surprising news: They say the 1918 virus was no super-bug. Instead, its deadliness had to do with how very different it was from the flu viruses circulating 25 or 30 years before, when the young adults of 1918 were first exposed to the flu.
Indeed, the new study says it’s that first childhood exposure that determines how people will fight off – or fall prey to – every other flu virus they will encounter in a lifetime.
That’s a very different way of looking at flu, both pandemics and regular seasonal outbreaks.
Much of the current emphasis is on the virus itself. Scientists around the world are doing controversial “gain-of-function” experiments – adding and subtracting pieces of genes from flu strains to see what mutations make some viruses so virulent.
Instead of focusing on flu virus itself, authors of a paper published Monday in the Proceedings of the National Academy of Sciences say scientists and public health experts should pay attention to the vulnerabilities of different age groups to any new flu virus – and how those immune gaps might be filled in by targeted vaccine strategies.
“Childhood exposure seems to give kick-ass immunity to that kind of flu virus for many, many decades,” says evolutionary biologist Michael Worobey of the University of Arizona, the paper’s lead author. Continue reading