Top White House economic officials published a study last year warning that up to 500,000 Americans could die in a pandemic that could also inflict $4 trillion of damage to the economy.

"Tens of millions of people could become ill, with many requiring hospitalization; and a significant number—especially among the vulnerable elderly population—could die," the study said.

The study, first published by The New York Times, undermines the Trump administration's argument that the public health and economic crises from the virus were unexpected.

Visit Business Insider's homepage for more stories.

White House economists published a study last September warning the Trump administration that a pandemic could cost up to 500,000 lives in the US and inflict $4 trillion of damage to the American economy.

First reported by The New York Times, the study — called Mitigating the Impact of Pandemic Influenza Through Vaccine — urged people to avoid conflating the risks from the seasonal flu and a pandemic caused by an easily transmissible virus.

"People may conflate the high expected costs of pandemic flu with the far more common, lower-cost seasonal flu," the study said. "It is not surprising that people might underappreciate the economic and health risks posed by pandemic flu and not invest in ways to reduce these risks."

The study also laid out how a pandemic could play out in the US.

"Tens of millions of people could become ill, with many requiring hospitalization; and a significant number—especially among the vulnerable elderly population—could die," the study said.

It was commissioned by the National Security Council, the newspaper said, citing two people familiar with the matter. The study also urged the federal government to ramp up its research and funding into vaccines.

Read more: 'Absolutely zero money out of my own pocket': How Jared Holland turned a little-known real-estate-investing strategy into screaming business — and nabbed a $120,000 profit on a 'free house'

As of Wednesday morning, the US has nearly 190,000 recorded coronavirus cases and the disease it causes — known as COVID-19 — has killed 3,000 Americans. It's compelled an economic shutdown of unprecedented proportions as businesses close their doors to curb the virus' spread. Increasing numbers of governors have placed people under stay-at-home orders.

For several weeks earlier this year, the Trump administration downplayed the public health risks from the coronavirus. White House economic officials compared the coronavirus to the flu, The Times reported.

"I don't think corona is as big a threat as people make it out to be," Tomas Philipson, acting chairman of the Council of Economic Advisers, told reporters in February.

Economists now expect the US to enter a recession, one that could very well surpass the severity of the one after the 2008 financial crisis.

The 2019 study blows a hole in the administration's argument that the pandemic's damage to the economy was unexpected. Earlier last month, the president said the pandemic was "an unforeseen problem" that "came out of nowhere."

The Trump administration recently extended federal social distancing guidelines until April 30. On Monday, public health officials said between 100,000 and 240,000 Americans could die from the coronavirus in the best-case scenario.

Read more: Stocks are trading like they did early in the financial crisis — and it's proof to one Wall Street equity chief that the coronavirus crash will worsen