Do I need a certified allergy barrier for severe dust-mite allergies?

For severe, medically diagnosed allergies, specialty barrier covers like the Mission: Allergy and premium microfiber encasements are built specifically around fabric pore size for allergen blocking, and they carry premium pricing to match. Mass-market OEKO-TEX encasements address dust mites too, but the specialty makers position their fabrics specifically for allergen barrier performance.