However from a certain viewpoint the only reported cases of polio have been caused by the polio vaccine itself! I dont have the studies on hand that make this claim but this is not an uncommon belief! But this is a whole other subject! And as in so many cases these virus are not a problem with those with a healthy immune system ! But I believe the vaccines and a comprimised immune system from toxins or anti biotics vsaccines is the real danger to ill health,and even Pasteur on his death bed rethought his position on pasteurisation with the statement that "the virus is nothing, the terrain everything"!