Allergy Mattress Covers?

I just found out that vinyl Mattress Covers are loaded with lead and phylates. I looked up rubber covers but the prices are outrageous, What is the alternative to that for allergies that is also waterproof?

There are so many manufactures of allergy Mattress Covers now. I would google to find out what is being offered now. Prices vary greatly among makers as well. Many will send you swatches.