Asia, where huge rural populations of humans live in intimate proximity to flu-infested fowl and animals, is a natural, massive and ever-bubbling cauldron for flu strains to circulate among species, to jump between species, to exchange whatever it is flu viruses exchange with each other, to mix their genetic material, and - here's the key - to mutate as a result of that mixing and then to emerge as new flu strains that infect humans. (That mix and match story, by the way, is the reason you need a new flu shot every year - the one from the year before is out of date pretty soon after it gets on the shelves).
.....So, that's what happens in Asia. But we've also learned over the years that the usual pattern for the rest of the world is that the strains of flu that are working their way through Asia in February and March are likely to be the same ones that will work their way to Europe and North America the following fall and winter, so those are the strains the experts recommend putting into "next year's" flu vaccine.
.....But why, then, you may well wonder, don't these experts wait until say, July or August to see which flu strains are indeed circulating across the globe and then to recommend those strains of the virus be put into the coming winter's flu vaccine formulation?
.....Because unfortunately, it takes vaccine makers several months at least to prepare enough vaccine for a useful immunization program, and they simply can't get the job done if they wait to ramp up production in the late summer or fall.
.....Clearly, then, you can see the huge problem in getting it dead on: the experts have to take an educated guess 6-8 months in advance as to which viral strains are likely to emerge from the many circulating simultaneously as the ones that should go into the flu formulation for the following winter.
.....Those poor guys. I mean I can't even predict in the late afternoon what my wife will want for dinner that evening, let alone which fish or veggie mixture she'll want me to serve her 40 weeks from today, but that's the equivalent of what these guys have to do.
.....That said, overall, the experts have had a |
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