Researchers investigated if people who have been in hospital with COVID-19 are at higher risks of hospital admission and death, either overall or for specific illnesses, compared with people in the general population, and people who have been hospitalized with influenza.

• In this cohort study, people who had hospitalized with COVID-19 (n = 24,673) were compared with people with similar demographic characteristics in the 2019 general population (n = 123,362), and people who had been hospitalized with influenza in 2017 to 2019 (n = 16,058) with respect to their risks of hospitalization and death, overall and for a range of specific causes.

• People who had had a COVID-19 hospitalization were more than twice as likely to be rehospitalized or die more than a week after discharge, with greater risks overall and for a range of specific causes when compared with people in the general population.

• Broadly similar or lower risk of several outcomes was recorded for COVID-19 patients compared with influenza patients, but there appeared higher risk of death overall, readmissions or death due to the initial infection, and dementia death in COVID-19 patients.

• Increased monitoring of patients in the months following hospital discharge, and greater awareness among patients and clinicians of potential problems might minimize or mitigate the risks.