The encouraging numbers indicate that it may soon be time to reopen much of the U.S. economy, Trump and some of his most senior aides have suggested in recent days. But the president insisted Friday he did not take the prospect lightly.

“I’m going to have to make a decision, and I only hope to God that it’s the right decision. But I would say, without question, it’s the biggest decision I’ve ever had to make,” he said.

Health officials are cautioning that most Americans will not be able to resume their normal lives on May 1, when the administration’s guidelines aimed at countering the coronavirus are set to expire.

A group of state health officials, working with researchers at Johns Hopkins University, released a detailed plan Friday calling for a “robust and comprehensive system to identify all Covid-19 cases and trace all close contacts of each identified case” before any economic reopening. The plan envisions a vastly bolstered testing regimen and an army of some 100,000 workers and volunteers — far above what the federal government currently has on hand — as well as $3.6 billion in emergency funding.

Trump’s health advisers, meanwhile, urged Americans to continue following federal recommendations first issued in mid-March and extended last week until the end of April to “stop the spread” of the disease, even as they contemplate when and where to relax them.

“There are places around the country that have seen consistently low levels. And as we ramp up testing and can feel more confident that these places actually can do surveillance and can do public health follow-up, some places will be able to think about opening on May 1,” Surgeon General Jerome Adams said Friday in an interview with Fox News.

“Most of the country will not, to be honest with you, but some will,” Adams continued, “And that’s how we’ll reopen the country: place by place, bit by bit, based on the data.”

Lifting social-distancing restrictions too soon “could lead to a deadly resurgence” of the disease, WHO Director General Tedros Adhanom Ghebreyesus warned Friday in Geneva. “The way down could be as deadly as the way up if not managed correctly.”

The health officials’ remarks do not directly contradict the optimism expressed by the president’s economic advisers. And even Dr. Anthony Fauci, America’s top infectious disease expert, now says he is seeing signs that the wave of unprecedented lockdowns are working in parts of the country.

But while Trump’s economic aides are floating an aggressive schedule for lifting federal guidelines to “slow the spread” of the disease, his health team is flashing a yellow light.

The contrast has been particularly striking over the last few days. White House economic adviser Larry Kudlow told POLITICO Tuesday it was possible to restart the economy “in the next four to eight weeks,” and Treasury Secretary Steven Mnuchin endorsed a prediction Thursday on CNBC that “we could be open for business in the month of May” if public health experts approve.

Meanwhile, the president is leaning hard into the hope that the economy will soon be ready to roar back to life. “There’s something good going to happen. I really believe that. There’s something very good going to happen. We have to get back,” Trump said Friday.

Fauci appeared less confident at the briefing, telling reporters that while “we are starting to see the leveling off and the coming down” of coronvirus-related metrics, Americans must keep up their social-distancing practices.

“This is not the time to feel that since we have made such [an] important advance in the sense of success of the mitigation that we need to be pulling back at all,” he said.

Other health officials are stressing the practical hurdles that currently stand in the way of lifting the federal guidelines. For instance, reopening the country would require a “substantial expansion of public health fieldworkers” to help monitor Americans who have come into contact with those who are infected, Dr. Robert Redfield, director of the Centers for Disease Control and Prevention, said Thursday.

More than 600 CDC employees are stationed around the country assisting with coronavirus response efforts, Redfield told NPR, but the agency is “going to have to substantially amplify” that workforce to ramp up contact tracing.

“Obviously, if we’re going to try to get this nation back to work shortly after the end of this month, we’re far along in those planning processes, as we speak,” he said, though he declined to specify how just far.

State and local officials grappling with the outbreak, who will ultimately be responsible for lifting the restrictions in their areas of responsibility, sounded positive notes even as they urged their citizens to stick to the directives.

Although New York, the epicenter of the outbreak in the U.S., recorded 777 deaths Thursday, Gov. Andrew Cuomo nonetheless pointed to a rare bright spot at his daily news conference Friday: The statewide headcount at intensive care units was down 17, the first decline since the outbreak began.