The study reports on how commonly nine core long-COVID symptoms were diagnosed, and how this rate compared to people recovering from influenza. Severity of infection, age, and sex affected the likelihood of long-COVID symptoms: long-COVID symptoms were more frequent in those who had been hospitalised, and they were slightly more common in women. Many patients had more than one long-COVID symptom, and symptoms tended to co-occur more as time progressed. Long-COVID symptoms did occur after influenza, but were 1.5 times more common after COVID-19. This study does not explain what causes long-COVID symptoms, nor how severe they are, nor how long they will last.
