In this paper we used the MSA− space, η−open sets and αη-open sets to introduce a new approximation of uncertain sets as a mathematical tool to modify the approximations. Moreover, several important measures such accuracy measure and quality of approximation would be studied. We compared the previous methods with the current one we obtained. We proved that minimal structure is more efficient and accurate in obtaining results than topology. Our newMαη−approximation space is more accurate than MSA− space , η−approximations and αη−approximations since by using it the boundary regions decreased by increasing the lower approximations and decreasing the upper approximations. Finally we show the importance of our new approximations with medical science by applying these approximations in corona virus problem.