In a major study, researchers have found that delirium -- a state of acute confusion associated with a higher risk of serious illness and death -- is a key symptom of Covid-19 in frail, older people.

The findings, published in the journal Age and Ageing, highlight that doctors and carers should be aware of delirium as a possible early warning sign of Covid-19 in the elderly, even in the absence of more typical symptoms such as cough or fever.