This is very true and undeserving of the downvotes. A vaccine can work globally, but it is not at all guaranteed. This is because the distribution of certain a

This is very true and undeserving of the downvotes. A vaccine can work globally, but it is not at all guaranteed. This is because the distribution of certain alleles, fundamental for the immune system, is heavily biased geographically [1]. [1]: http://pypop.org/popdata/ http://pypop.org/popdata/