Naturally, you want to make sure your protector has a zipper and laminated fabric (or mentions “waterproof and “stain- and spill-resistant” in the description). But beyond that, if you’re looking for an allergen-free protector, you want to make sure it has a certification from the Allergy Foundation of America. This means that, if you see a “CERTIFIED asthma & allergy friendly” label on the outside packaging, the protector has been successfully tested to meet the following set of criteria: 
- Features an outer fabric that blocks allergens like dust mites from passing through
- Is “breathable”
- Can be easily cleaned to remove allergens
- Can withstand the wear and tear of the recommended cleaning techniques
- Contains no chemicals known to trigger asthma and allergy symptoms
Read the full article on PureWow.