A new study is providing insights into the 2009 swine flu epidemic, and why more serious complications arose in healthy middle-aged people than expected. The researchers say the culprit may be antibodies to seasonal flu found in the seriously ill patients, which might have caused an immune system overreaction in the lungs.
“Nobody really had a good explanation for why middle-aged people seemed to have more severe disease than would have been expected,” says Richard Scheuermann, an immunologist at the University of Texas Southwestern Medical Center in Dallas. “This explanation is the first one that I’ve seen that actually makes sense.” [Nature News]
Normally, severe flu illness happens in the very young (who haven’t been previously exposed to the flu and don’t have protective immunity) and the elderly (who have weakened immune systems). Instead of affecting these groups, the 2009 pandemic H1N1 “swine flu” primarily caused severe reactions in middle-aged adults.
An extensive study conducted on school children in Western Canada has proved that immunizing kids and adolescents goes a long way towards protecting the entire community from communicable diseases like the flu, thanks to a phenomenon known as “herd immunity.”
The findings come at a time when vaccine phobia is one of our largest public health concerns, with many parents worrying that immunizing kids can lead to adverse side affects. A recent survey revealed that one in four U.S. parents think that vaccines might cause autism, probably due in part to a 1998 paper published in the journal The Lancet that wrongly linked autism to vaccines–that paper has since been refuted, and fully retracted by the journal.
Now, scientists have more evidence that vaccines provide a public health benefit. Researchers studying youngsters in 49 remote Hutterite farming colonies in Canada found that giving flu shots to almost 80 percent of a community’s children created a herd immunity that helped protect unvaccinated older people from illness. As children often transfer viruses to each other first and then pass them along to grown-ups, the study provided solid proof that the best way to contain epidemics like the recent H1N1 outbreak is to first vaccinate all the kids. By immunizing the most germ-friendly part of the herd first, you indirectly protect the rest of the community, scientists say.