The World Health Organisation (WHO) experts and a range of other scientists said on Monday there was no evidence to support an assertion by a high profile Italian doctor that the coronavirus causing the Covid-19 pandemic has been losing potency.

Professor Alberto Zangrillo, head of intensive care at Italy's San Raffaele Hospital in Lombardy, which bore the brunt of Italy's Covid-19 epidemic, on Sunday told state television that the new coronavirus "clinically no longer exists".