A U.S. media outlet said forecasts on the global economy were turned "upside down" by the news on U.S. pharmaceutical company Pfizer and German firm BioNTech's COVID-19 vaccine candidate.

On Monday, Bloomberg cited Torsten Slok, chief economist at private-equity firm Apollo Global Management, who said the news is a "game changer" that will "turn all forecast spreadsheets upside down."

While the International Monetary Fund(IMF) downgraded its forecast for next year less than a month ago, Bloomberg said the possibility of a vaccine being manufactured and distributed early next year may warrant significant revisions for the first quarter.

Despite a gloomy outlook for the fourth quarter this year due to the virus' resurgence in the United States and Europe, the report said hope for a vaccine has the potential to boost confidence among consumers and companies, and support spending and hiring.

Some economists, however, are being more cautious about revising forecasts, with James Sweeney, chief economist at Credit Suisse Group AG, saying he would need to "see the vaccine out and in place" before making a material change.