SEATTLE — An innovative coronavirus testing program in the Seattle area — promoted by the billionaire Bill Gates and local public health officials as a way of conducting wider surveillance on the invisible spread of the virus — has been ordered by the federal government to stop its work pending additional reviews.
The program involved sending home test kits to both healthy and sick people in the hope of conducting the kind of widespread monitoring that could help communities safely reopen from lockdowns. Researchers and public health authorities already had tested thousands of samples, finding dozens of previously undetected cases.
But the program, a partnership between research groups and the Seattle and King County public health department that had been operating under authorization from the state, was notified this week that it now needs approval directly from the federal government. Officials with the Food and Drug Administration told the partnership to cease its testing and reporting until the agency grants further approval.
“Please discontinue patient testing and return of diagnostic results to patients until proper authorization is obtained,” the F.D.A. wrote in a memo.
The delay is the latest evidence of how a splintered national effort to develop, distribute and ramp up testing has left federal regulators struggling to keep up. Amid concerns about the reliability of a burgeoning number of coronavirus antibody tests — which check whether someone may have previously had the virus — the F.D.A. responded last week by ordering companies to submit data proving the tests’ accuracy.
But the Seattle program does not test for antibodies and has wide backing, including from public health leaders, the Fred Hutchinson Cancer Research Center and Mr. Gates, whose foundation has been deeply involved in fighting the pandemic. The Centers for Disease Control and Prevention also provided an in-person technical adviser to the project.
Dr. Eric Topol, the director of the Scripps Research Translational Institute, who is not involved in the Seattle group, said it had “emerged as leading lights in this whole Covid-19 crisis.” He said it was “bizarre” that the F.D.A. would halt such a project.
The Seattle partnership that is conducting the testing, the Seattle Coronavirus Assessment Network, said in a statement that it had been in conversation with the Food and Drug Administration about its program for about 10 weeks and submitted data a month ago.
“We are actively working to address their questions,” the group said.
The program has roots in the Seattle Flu Study, which over the fall and winter had collected thousands of samples from people in Washington State who had symptoms of illness. As previously detailed in The New York Times, researchers there had struggled to get government approval to test those old samples for the coronavirus and report the results.
By the end of February, those researchers ended up doing some testing anyway, discovered the first case of community transmission in the region and provided key evidence that the virus had most likely been circulating for weeks.
Mr. Gates, the Microsoft co-founder who has committed much of his wealth to global public health issues, has backed the Seattle study. He said in a blog post Tuesday that the program could detect cases and help guide public health responses.
“Not only will it help improve our understanding of the outbreak in Seattle, it will also provide valuable information about the virus for other communities around the world,” Mr. Gates wrote.
An F.D.A. spokesperson said home collection kits raised additional concerns about safety and accuracy that required the agency’s review. The issue in the Seattle case appears to be that the test results are being used not only by researchers for surveillance of the virus in the community but that the results are also being returned to patients to inform them.
The two kinds of testing — surveillance and diagnostic — fall under different F.D.A. standards. In a pure surveillance study, the researchers may keep the results just for themselves. But coronavirus testing has largely revolved around getting results returned to doctors who can share the results with patients.
“We had previously understood that SCAN was being conducted as a surveillance study,” the spokesperson said.
Private companies have also rushed to promote at-home test kits, and the F.D.A. approved the first one available for purchase in April.
Dr. Topol said it would not make sense to have people swab their noses and then not give them their test results.
“To withhold that information from people is downright absurd,” Dr. Topol said.
At-home testing kits have been praised as a valuable alternative to in-office or drive-through testing because they do not require a clinician to risk exposure when swabbing a patient’s nose. They have also emerged at a time when public health leaders are looking for ways to rapidly expand testing to look for hot spots and trends.
Dr. Topol said the country probably needed to ramp up to do millions of tests daily. The infrastructure needed for expansive drive-through testing would be difficult to achieve, he said, and could miss people who do not want to leave their home to drive to a site.
“Home testing is really the only way we can get massive testing in the United States,” he said.
The Seattle testing group said it had been in conversation with the F.D.A. since the beginning of March and initiated the process to obtain federal approval on March 23. That process included submitting data from testing so far on April 13.