Dr Donald Yealy, chair of emergency medicine at UPMC, explained at a press conference on Thursday that people seem to be contracting the virus less easily and cases appear to be less severe then when the pandemic first took hold in the US early this year.
'The virus may be changing,' Yealy said. 'Some patterns suggest the potency is diminished.'
He noted that UPMC has successfully treated more than 500 coronavirus patients since March, and in recent weeks fewer patients are requiring ventilators to help them breathe.
The doctors' findings that the virus could be declining in potency came days after researchers in Italy announced that patients there were showing much smaller amounts of the virus in their system, compared to samples taken during the peak of the crisis in March and April.
Professor Alberto Zangrillo, head of intensive care at Italy's San Raffaele Hospital in Lombardy, went so far as to say that the virus 'clinically no longer exists' during a Sunday interview on state television.
But World Health Organization experts and a range of other scientists quickly rejected Zangrillo's claims on Monday, saying there is no evidence to support the assertion that the coronavirus has been losing potency.