[Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] [Tag] This is very very rare. Of course it has ocurred w oral polio vaccine to some extent but the benefits of getting rid of nearly all polio cases far outweigh the relatively very small number of vaccine derived polio.