Probably the OP refers to a large scale Israeli study from late summer.

https://www.science.org/content/article/having-sars-cov-2-on...

https://www.medrxiv.org/content/10.1101/2021.08.24.21262415v...

Edit. While googling around on this topic, I stumbled upon a decent comparison between the Israeli study and a CDC study that claims the opposite, specifically that covid recovered are five times more likely to be hospitalized for covid than the vaccinated.

https://brownstone.org/articles/a-review-and-autopsy-of-two-...