Did you realize that your mattress is the dirtiest item in your house? You clean everything that you own; your-self, clothes, floors, walls, counters, sinks, bathrooms, carpets, drapers, cars, pets, phones, etc. But, never your mattress? Changing sheets, allergy mattress cover, or dust allergy bedding will not keep your mattress sanitary! In fact covers will have more of an adverse effect because of the lack of oxygen.
You spend 1/3 of your life sleeping on your mattress. Mattress cleaning is a huge part of any effective anti allergen cleaning and maintenance routine.