How scientists predict the flu's viral future

Getting a flu shot is like voting: most people know it’s a thing they’re supposed to do, and yet millions of Americans skip it. In both cases, there’s a lot of apathy involved, and more than a little skepticism: does my vote actually count? Does this flu shot actually do anything?
Well, yes and yes, but let’s focus on flu vaccines.The path to your shot starts months before you ever see a needle. Twice a year, experts evaluate all the flu strains spreading across the Earth