Population Study: Past Covid-19 confers 80.5% protection against reinfection, which decreases to 47.1% in those aged 65 years and older

Assessment of protection against reinfection with SARS-CoV-2 among 4 million PCR-tested individuals in Denmark in 2020: a population-level observational study – The Lancet

Commentaries: Risk of SARS-CoV-2 reinfection after natural infection – The Lancet AND COVID-19 Reinfection: More Common Than We Think? – MedPage Today (free registration required)

Commentary on Twitter

NEW—Most people who have had original #COVID19 strain are protected from catching it again for at least 6 months—but those ≥65 years are more prone to reinfection, suggests first large-scale study of its kind. Read https://t.co/250Yv0a9BZ pic.twitter.com/BTjhcMzXwT

— The Lancet (@TheLancet) March 17, 2021