Hi LoveWarrior,
It’s not off topic at all … and it’s a choice almost everyone will need to make 
Post #89 here and the posts it links to have more information about the pros and cons of different types of mattress protectors and some links to some good options but it seems to me that a waterproof membrane type of protector (such as the type that jankdc linked) would make a good choice to protect against accidents.
Phoenix