Here is a great article recently released by Arlene Shulman .
It was something done in the past. Vinyl and plastic that was used then is no longer available today.
So most slipcovers are now made from fabric these days. Do read the article. I loved it! https://www.nextavenue.org/elegy-to-plastic-slipcovers/
Maria Lizardo (right) and friend | Credit: Courtesy Maria Lizardo