My idea was to sew a book cover of a nice fabric to protect the booklet. I thought this would be useful for other parents too, as most families have such booklets. So I made some extra covers to sell at my Christmas fair.
Just measure the book, add the two parts that are folded to the inside of the cover, and add the seam allowance for the part along the top and the bottom edge of the book. The easiest way is to make a pattern or template of paper or thin cardstock.