After the first 3 months, natural immunity was associated with a 95% lower risk of SARS-CoV-2 infection and an 87% lower risk of COVID-19 hospitalisation for up to 20 months.
The risk of SARS-CoV-2 reinfection and COVID-19 hospitalisation in individuals who have survived and recovered from a previous infection remained low for up to 20 months. Vaccination seemed to further decrease the risk of both outcomes for up to 9 months, although the differences in absolute numbers, especially in hospitalisations, were small.
