The U.S. FDA is no longer reviewing lab-developed tests (LDTs) under the emergency use authorization (EUA) program, which eliminates product liability protection for them under the Public Readiness and Emergency Preparedness (PREP) Act. Harvard’s Michael Mina said on an Oct. 30 press briefing that the PREP Act question could be extended to LDTs administratively even outside EUA review, a move he said is under consideration based on his communications with Assistant Secretary for Health Brett Giroir.
Tim Stenzel, director of the FDA’s Office of In Vitro Diagnostics and Radiological Health, announced the decision to skip EUA review of LDTs early in October, a change that came after the Department of Health and Human Services (HHS) decreed that the agency has limited statutory authority to regulate such tests. When asked whether labs should continue filing EUA requests despite the lack of review, however, Stenzel was noncommittal, although there were indications that this particular question would be revisited.
Mina, a professor of epidemiology at the Harvard Chan School of Public Health, said during the briefing that most of the labs already had their EUA applications in for COVID-19 testing by the time of the FDA policy change. However, he said the lack of EUA review “is hugely damaging to our ability to continue scaling up testing.”
One of the issues is that any entity interested in partnering with a lab will want to see an EUA for that lab’s test, particularly as that authorization has become a de facto stamp of approval, Mina said. The situation also disallows any lab with a new and potentially superior test from gaining traction in the market if it did not get its EUA application to the FDA prior to the policy change.
Mina said he has been trying to persuade Giroir to change the PREP Act policy to include LDTs that are practiced outside EUA authorization. Giroir has been responsive, but Mina said he is not clear on why there has been so little movement at HHS. The question may be under consideration by HHS legal staff, but Mina pointed out that PREP Act coverage has been extended to point-of-care antigen tests for use in nursing homes and other residential facilities.
First in-home tests may be small volume productions
The FDA could issue an EUA for a fully home-based test in the next couple of weeks, and Mina said the first test or two of this type might not be produced in particularly large numbers. However, he noted that neither the FDA nor the Centers for Disease Control and Prevention has offered much guidance as to how to deploy high-volume tests, such as the Abbott Binax Now.
“I think these tests hold immense power” to corral the pandemic, Mina said of rapid antigen tests – to include the Binax Now – and can be used to halt the spread of the SARS-CoV-2 virus across large swaths of population in smaller test volumes than might be expected if strategically deployed. One of the best uses might be serial testing of individuals, but Mina said he is not confident that the first series of tests for home use “will make much of a dent at all.”
Mina said the FDA may be gradually warming up to the idea of using antigen tests on asymptomatics, but that the agency seems to have failed to consider that in order to document the test’s sensitivity, the sponsor must find subjects early in the infection phase. The larger point, however, may be that the FDA still has not created a regulatory pathway for tests that are intended for public health vs. diagnostic purposes. This could be done without lowering the bar for testing conducted to establish a diagnosis, Mina asserted.
Many nursing homes are receiving results from PCR tests three to four days after they were administered, but Mina said that even a 24-hour turnaround is insufficient for these facilities because of the vulnerability of the residents. A better approach might be a less sensitive POC test that is used on all who enter the building. Mina acknowledged, however, that confirmatory testing for first-test positives would struggle to match that pace. He also said that just as nursing home and other facility residents are sequestered by test status, the staff working in these locations perhaps should be as well.
Mina criticized the Trump administration for committing an “extraordinarily minimal number of dollars to testing,” even though testing is one of the most important tools for stopping the spread. He reiterated his support for paper-strip testing methods but added that the colder weather now settling in over the Northern Hemisphere is almost certain to generate a spike in diagnoses as time spent outdoors shrinks. Some grade and high school systems are working on partial returns, in some instances a response to students who are falling desperately behind in their academic progress. Because of all these factors, “we could end up seeing this thing continuing to skyrocket over the next few months,” he said, adding that a daily positive case volume of 200,000 would not surprise him.
Testing strategy better left to federal government
Mina said college students going home for Thanksgiving present some risks to their home communities. However, the greater risk may be when students return for classes. Any living rearrangements, even short-lived ones, such as holiday breaks, are prime turf for spikes in infection rates. HHS recently posted data on how the states are deploying the nearly 100 million Binax Now tests distributed to date, with deployment varying considerably, depending on where officials see the greatest need. Still, Mina advocated a national test deployment strategy rather than leaving such decisions to the governors.
Colleges and universities might consider testing students before they leave for Thanksgiving, but Mina acknowledged that not all schools have the requisite resources. Many institutions have discouraged students from going home after a positive test result.
If the goal is to safely reopen the economy, there are few options at this stage, Mina said. “We’re in the thick of a third spike, or a second spike, depending on where you are,” he added, cautioning that he is nonetheless not a fan of a full shutdown of the economy. One of the few remaining options in the absence of a vaccine might be to lend a little more vigor to compliance with masking recommendations and social distancing.