Natural Immunity for the Win- 3 studies

Here, we evaluate 254 COVID-19 patients longitudinally up to 8 months and find durable broad-based immune responses. SARS-CoV-2 spike binding and neutralizing antibodies [have] an extended half-life of >200 days suggesting the generation of longer-lived plasma cells… Taken together, these results suggest that broad and effective immunity may persist long-term in recovered COVID-19 patients.  https://www.medrxiv.org/content/10.1101/2021.08.19.21262111v1.full

Not one of the 1359 previously infected subjects who remained unvaccinated had a SARS-CoV-2 infection over the duration of the study. https://www.medrxiv.org/content/10.1101/2021.06.01.21258176v2 

Israeli researchers looking at a much larger group of people also found very, very low reinfection rates. Only 19 out of 16,215 people with natural immunity had a second infection from June 1 to August 14 (far fewer than the number of vaccinated people who were infected in a matched group).https://www.medrxiv.org/content/10.1101/2021.08.24.21262415v1.full-text