https://www.medrxiv.org/content/10.1101/2021.04.19.21255739v1 https://www.medrxiv.org/content/10.1101/2021.04.19.21255739v... <- natural immunity is pretty long

https://www.medrxiv.org/content/10.1101/2021.04.19.21255739v1 https://www.medrxiv.org/content/10.1101/2021.04.19.21255739v... <- natural immunity is pretty long-lived https://www.medrxiv.org/content/10.1101/2021.08.24.21262415v1 https://www.medrxiv.org/content/10.1101/2021.08.24.21262415v... <-- 6x better than fresh vaccine after a year or so, 13x better in a 4-6 month period after