A group from Cornell University, Doha, Qatar, etc. has reported how much risk is there in reinfection of SARS-CoV-2.
https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(21)00141-3/fulltext
Among 43,044 individuals with SARS-CoV-2 antibody-positive from Apr. 16th to Dec. 31th, 2020, persons with PCR-positive swab ≥14 days after the first-positive antibody test were thought to be reinfected.
As a result of this study, the efficacy against reinfection was estimated at 92.7% (95% CI: 91.3–93.9%). It is so interesting that this efficacy estimate is similar to the efficacy reported for the two mRNA COVID-19 vaccines, and reinfections were less severe than primary infections. That is good news for all of us.