In late February and early March, as the incidence of COVID-19 began to skyrocket in the United States, the dominant story was one of inaction: a shortage of diagnostic tests hamstrung health systems and public health departments from accurately tracking the spread of the virus. FDA at the time permitted only one diagnostic test, developed by CDC, to be used to test for the virus.
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But as demand outpaced supply FDA loosened regulatory restrictions in an effort to meaningfully expand access to diagnostic testing nationwide. The main lever at their disposal was guidelines around Emergency Use Authorizations, or EUAs. FDA on Feb. 4th issued the first EUA to CDC, and then last week issued nine new EUAs, more than doubling the number of entities making diagnostic tests for COVID-19.
What are EUAs?
When the HHS Secretary declares a public health emergency for the sake of expanding access to medical care, the FDA Commissioner may approve the use of unapproved medical products to diagnose, treat, or prevent diseases or conditions when there are no "adequate, approved, or available alternatives." In such cases, organizations may submit EUA requests to enable them to deploy validated products that are able to meet the demonstrated need.
EUAs were first introduced as part of the Project BioShield Act of 2004 as a protective measure against weapons of mass destruction and were most recently issued in response to the Zika virus, Enterovirus, Ebola virus, MERS, and the Avian flu.
FDA requires a lower burden of evidence for an EUA than it does for standard FDA approval. There is more flexibility around the "amount, type, and quality" of evidence that is considered acceptable for a successful EUA application. EUA applicants must simply demonstrate that the product "may be effective" in diagnosing, treating, or preventing the relevant condition. Those applications are approved on a case-by-case basis based on available evidence and a risk-benefit analysis.
How are EUAs increasing COVID-19 testing capacity in the US?
The EUA process has ramped up rapidly in the past week, significantly expanding the availability of COVID-19 tests to help alleviate the testing constraints many hospitals were facing. On Feb. 29, FDA issued guidance permitting CLIA-certified labs to deploy validated tests prior to submitting formal EUA requests (as long as they submit a request within 15 days of test deployment). On March 16 FDA extended the guidance to commercial manufacturers of diagnostic test kits. While the guidance had little effect for some labs already working through test development, it enabled others to more rapidly get their products to a market desperate for supply.
The companies granted EUAs for coronavirus tests range from large corporations like Quest Diagnostics and LabCorp to smaller companies like DiaSorin and Primerdesign. And while many providers are still facing lags in testing, we're already seeing growth in testing capacity: Quest Diagnostics stated that it expected to be able to run 20,000 tests per day this week, and 280,000 tests per week by April 1. As of Wednesday morning, 16 entities have received EUAs for COVID-19 tests, with roughly 50 more expected in the next few weeks.
What is the latest development?
On Friday March 20, FDA issued the first EUA for a rapid testing kit that will be available at the point of care. The Xpert Xpress SARS-CoV-2 test from Cepheid can either be performed in high-complexity, CLIA-certified labs or, beginning March 30th, "certain patient care settings."
Cepheid was the first lab to receive an EUA for point-of-care testing since the outbreak began, but Mesa was quick to follow on Tuesday March 24, and others are in the pipelines. The ability to test patients quickly—Cepheid cites a 45 minute turnaround time, and Mesa claims 30 minutes—will improve provider workflow by reducing the steps- and time- from patient triage to result delivery. It will also make it easier to provide patients with clear treatment plans (i.e., self-quarantining), which is essential to limit the spread of the disease.