Abstract: The invention relates to virus vaccines and to a process for the preparation thereof especially to polio virus vaccines and other picorna virus vaccines, such as foot-and-mouth disease vaccine.The invention provides vaccines which are stabilized and show an improved activity by the addition of compounds of formula I of the formula sheet, in which R.sub.1 en R.sub.2 each represent an alkyl- or alkoxy group of not more than 6 carbon atoms, preferably not more than 4 carbon atoms,A represents a bivalent hydrocarbon radical of 3-12 carbon atoms,R.sub.3 represents an unsubstituted or substituted phenyl radical and n is 1 or 0.