Based on 4 million Danes who received multiple PRC tests in 2020, researchers at Denmark’s SSI (Statens Serum Institut) have calculated the average person is about 80% protected – at in the short term – against reinfection with COVID-19.
Among those aged 65 and over, however, that protection is estimated to be only 47%.
This protection is assumed to last at least 6 months. Once again, these results are based on the older, `wild type’ COVID, not the recently emerged variants carrying the E484K mutation, and so these numbers may not hold going forward. Source: Avian Flu Diary: Denmark SSI: Assessment of Protection Against Reinfection with SARS-CoV-2