There are many distributors online which have the covers, or you can even find them at Target. Some are nicer, higher quility, and more comfortable than others. My doctor tends to say she is a minimalist as far as what a person can do to help with allergies, espescially dust and dust mites. The mattress and pillow covers are really helpful because dust is problem because it settles on surfaces, so then we lay down in the dust and dust mites. We are allergic to the dust mites digestive elements, so you should always wash your bedding in hot water. My doctor said that the air purifier probably would not be necessary but if I could find one that might help, that isn't too expensive, that it couldn't hurt. Although, the ozone producing ones can be harmful, and typically are problematic for people with asthma. Specifically, the IonicBreeze is supposed to be harmful. That's about all I know though.