The IMF chief said in her press conference on Friday that this recession would be even worse than in 2009.
It triggers the distribution of millions of relief checks of up to $3,400 for an average American family of four.
The unprecedented $2 trillion plan helped spur a surge across global equities as panicked traders worried about the impact of the coronavirus.
The crash will almost certainly be accompanied by a surge in unemployment, especially in countries with weaker worker rights, such as the US.
While the deadly disease continues to spread, traders have a rare semblance of optimism.
The COVID-19 outbreak has brought the European economy to it knees and Italy, with the backing of France and Spain, wants a massive response from EU partners.
The negative mood was fuelled by the failure of US lawmakers to agree on a trillion-dollar emergency package to help the reeling American economy.
Monday's "social distancing" announcement sparked concern about the impact on business, especially in the hospitality industry.
Airlines and airports are also large employers, accounting for around four million jobs worldwide.
There is a broad consensus that the disease, which has wiped trillions off market valuations, will cause a global recession.