We have a grandbaby girl, who has given the waterproof mattress protector on her mother's mattress "The Acid Test" several times.
The waterproof mattress protector that continually saved her mattress, is the Danican Silver Tech model...and has never failed.
The Silver infused cotton sleeps cool. it fits up to 15" and doesn't shrink when washed in hot water.
Here's a link to their site. You can order from the factory, directly.
There are several health reasons to get a Danican® protector to keep your pillow and mattress clean and there is always the “ick” factor. Moisture in your bed can break down the materials and also cause mold, bacteria, viruses, or fungus to grow.