Senior White House officials have in the past few days studied how much funding they have available to respond to the omicron variant, as the Biden administration makes contingency plans to deal with the next potential stage in the pandemic, three people familiar with the matter said.

The review comes amid fresh tremors on Wall Street related to omicron and the economy’s outlook. The CEO of Moderna alarmed investors Tuesday when he warned that vaccines might not be as effective against this particular variant. Several hours later, Federal Reserve Chair Jerome H. Powell spooked financial markets even more when he said the central bank could speed up the relaxation of its emergency measures amid concerns about inflation.

The burst of uncertainty comes as government officials try to ascertain both the health and economic risks posed by omicron, a new variant of the coronavirus that was recently detected in southern Africa but is now in multiple countries. The White House Office of Management and Budget and senior Biden administration health officials are working to determine exactly how much remaining funding they have that could be redirected to new problems arising from the variant.

Congress and the White House approved trillions of dollars in emergency funds starting last year to combat the virus’s spread and try to minimize any economic fallout. Officials are working to determine which accounts still have unused funds that could be diverted if omicron creates new challenges.

Stock markets have fluctuated wildly on confusion about whether omicron will prove as risky and deadly as the delta variant did several months ago. Many parts of the economy are already in flux, with consumer confidence trending weaker, inflation trending higher, but the labor market and growth snapping back into stronger positions. There have been signs in recent days that supply chain logjams are loosening, but a fresh round of covid concerns could close some factories and create new delays, driving up the costs of goods and worsening inflation.

Powell said that because of already high inflation “it is therefore appropriate in my view to consider wrapping up the taper of our asset purchases … perhaps a few months sooner.” The Fed had extended tremendous economic support to financial markets to keep the economy growing, but he effectively signaled Tuesday that this support could be pulled back faster than earlier estimates. This change in tone led the Dow Jones industrial average and S&P 500 to shed nearly 2 percent by the end of the day.

The White House covid coordinator said on Nov. 30 that the government is in discussion with the three vaccine manufacturers about modifications to the vaccines. (Whitehouse.gov)

Powell said the Fed would continue to monitor omicron as well as inflation and employment as it decides on the path forward.

Over at the White House, officials were working to understand their options but so far do not believe there is a need for an imminent request to Congress for more money. But that could change in coming days, the officials said, as much of the funding already approved for the White House to respond to the pandemic has been earmarked for specific purposes, such as free testing for uninsured Americans. White House officials are looking at how much money they would need in a worst-case scenario, in case the administration needs to immediately purchase mass quantities of vaccines designed to immunize specifically against the new variant.

The cost of updated vaccines for all Americans could run as high as $7.5 billion, while buying 2 million additional monoclonal antibody treatments could cost $4 billion, according to one senior administration official, who provided rough estimates. Another $5 billion for 10 million antiviral pills could bring the total to $16 billion, the administration official said. The administration official and two other people familiar with internal discussions spoke on the condition of anonymity to reflect private deliberations.

It is unclear whether the White House has enough funding flexibility to cover all the new potential sources of need. A spokesman for OMB declined to provide estimates of how much funding OMB believes is available to respond to the variant.

Budget experts say the federal government has billions of dollars in funds approved in prior legislation for pandemic-related measures. But precise external estimates are hard to come by because federal health funding is not reported in one singular place and is often jointly run by different parts of the federal government.

“They appropriated a lot of money for vaccine testing and tracing and all that stuff. But it’s been the hardest thing for us to track,” said Marc Goldwein, a budget expert at the Committee for a Responsible Federal Budget, which tracks federal funding. “My sense is there’s money in the bank — we appropriated a lot of money in the American Rescue Plan for pandemic purposes.”

A White House request for emergency funding could set off a messy political battle with the GOP, particularly as the two sides would likely have to agree on what existing federal resources to reallocate to the response to omicron. But G. William Hoagland, a senior vice president at the Bipartisan Policy Center, said he does not doubt that Congress would mobilize quickly to provide additional funding if necessary on a bipartisan basis to deal with the variant. He said that process would likely take a few weeks for health officials to gauge the likely health impact.

Hoagland said some of the funding set aside for pandemic response measures is earmarked for free coronavirus testing for the uninsured, which he said may limit how much extra money they have to shift without congressional approval.

“I think it’s far too early to determine ‘what is needed for omicron,’ but given our history if this becomes an issue I doubt there’s any question that the resources will be there,” Hoagland said. “I don’t see a domestic political fight happening over omicron.”

As the White House makes contingency plans, global markets shuddered Tuesday amid growing concerns that existing vaccines may not be enough to stop the highly mutated omicron variant.

Investors were shaken after Moderna chief executive Stéphane Bancel told the Financial Times and CNBC that coronavirus vaccines might be less effective against the new strain, and that new shots targeting omicron would be months away.

“Markets hate uncertainty, and this is precisely what we have now,” Russ Mould, investment director at AJ Bell, said Tuesday in an email. “No one knows how much trouble the new variant is going to cause, and so it seems plausible that we will see heightened volatility on the markets until there is adequate data to better understand the lay of the land.”

Oil markets were hit hard as nations including the United States rushed to restrict travel to try to keep omicron out. Brent crude, the international oil benchmark, slid more than 2.8 percent to trade around $71.13 per barrel. West Texas Intermediate crude, the U.S. oil benchmark, fell more than 2.6 percent to trade around $68.10.

Companies whose fates are tightly tethered to travel and the pandemic saw their shares fall sharply. Carnival, Royal Caribbean, Delta, United and American Airlines all fell 2 percent in early trading, as did Moderna.

President Biden expressed confidence on Monday that the United States can handle the new variant, saying it is “a cause for concern, not a cause for panic.” But the host of unknowns about omicron and its potential to set back the global recovery also “pose downside risks to employment and economic activity and increased uncertainty for inflation,” Powell said, according to his prepared remarks.

The uncertainty pushed investors toward safe havens. Gold rose nearly 0.5 percent to trade around $1,791 per troy ounce. The yield on the 10-year U.S. Treasury note sank 0.054 percent. Asian markets closed mostly in the red, with South Korea’s Kospi falling 2.4 percent and Hong Kong’s Hang Seng Index and Japan’s Nikkei 225 both shedding more than 1.5 percent. European markets were negative across the board in midday trading, with Germany’s DAX and France’s CAC 40 both logging declines of 0.8 percent or more.