On March 17, the Food and Drug Administration (FDA), the Centers for Disease Control and Prevention (CDC) and the Department of Health and Human Services (HHS) all took steps to improve access to COVID-19 screening. HHS announced that the CDC will use existing funding mechanisms to provide $10 billion to states to support COVID-19 screening testing for teachers, staff, and students. The CDC released additional guidance that emphasizes the role of screening tests at this phase of the COVID-19 pandemic, identifying widespread testing, regardless of signs or symptoms or known exposure, as a key component to mitigating the transmission of SARS-CoV-2 as outbreak prevention and control is thought to depend largely on the frequency of testing and speed of reporting.
The CDC explains that the appropriate frequency of testing will depend upon current community indicators for COVID-19 such as cumulative incidence and test positivity; the characteristics of the school, workplace, or another gathering (e.g. size, the proximity of people, and duration of interaction); and the incubation period for COVID-19 (up to 14 days). Testing using a tiered approach—where individuals most likely to be infected are tested first—could also be considered, and may be particularly important for low-incidence areas.
New Supplemental Template Available for Diagnostics Developers
Perhaps most notable for life sciences companies and laboratories developing diagnostics, the FDA issued a new supplemental template for developers seeking an Emergency Use Authorization (EUA) of certain tests for screening with serial testing. Recognizing the changing nature of the COVID-19 pandemic, by the end of 2020 the FDA was already shifting to prioritize EUA requests for tests where authorization would increase testing accessibility (e.g. point-of-care tests, home collection tests, and at-home tests) or that would significantly increase testing capacity (e.g. pooled testing, tests that reduce reliance on test supplies, or widely distributed tests). We previously authored an article for American Health Law Association outlining regulatory and legal reasons why the FDA had the authority to issue EUAs for at-home or screening testing; that article provides detailed information on the regulation of in vitro diagnostic products.
The streamlined path to authorization for these important screening tools applies to developers of molecular and antigen tests for use in serial testing programs, as well as at-home tests for use in a serial manner outside of a testing program with the intent to detect SARS-CoV-2 in asymptomatic individuals. This includes tests conducted in any location, including in a laboratory, at the point-of-care, or even non-traditional testing locations such as the home, offices, sporting venues, airports, or schools.
The typical COVID-19 tests developed up until this point have generally been geared toward providing a clinical diagnosis for individuals already exhibiting symptoms or who have had a known or suspected exposure to the virus. By contrast, serial testing involves testing the same individual multiple times within a few days to improve the chances of detecting an asymptomatic infection that might not show up if the individual had taken a single test.
Additions to the Existing EUA Process Made by the Supplemental Template
- The new FDA template supplements the recommendations in the Molecular Diagnostic Template for Commercial Manufacturers, Antigen Template for Test Developers, and Template for Manufacturers of Molecular and Antigen Diagnostic COVID-19 Tests for Non-Laboratory Use. Test developers should still use one of these referenced templates as their primary template and incorporate information from this supplemental template as applicable.
- The supplemental template should be used by developers of molecular or antigen diagnostic tests, for use in serial testing programs as well as tests for serial at-home use by individuals separate from a testing program, including to support authorization for over-the-counter use, intended to detect SARS-CoV-2 from individuals with or without symptoms or other epidemiological reasons to suspect COVID-19 infection.
- Proposed Intended Use: unlike previous EUA templates, the FDA recommends including the following requested intended use in the supplement: “…individuals without symptoms or other epidemiological reasons to suspect COVID-19 infection, when tested twice over two (or three) days with at least 24 hours (and no more than 36 hours) between tests.”
- Alternative testing intervals, such as testing every three days or testing twice a week (such as Monday/Thursday or Tuesday/Friday), may be considered for molecular or antigen tests intended for use as part of a testing program.
- A weekly testing interval may be considered for higher sensitivity molecular tests.
- Clinical Performance Evaluation: FDA recommends following the recommendations for clinical performance evaluation in the appropriate EUA template, except in the case of a screening claim with serial testing, FDA would generally expect labeling to indicate that testing is done twice over two (or three) days with at least 24 hours (and no more than 36 hours) between tests. Alternative testing intervals may be considered for molecular or antigen tests intended for use as part of a testing program.
- The developer should generally follow the clinical performance evaluation recommendations in the corresponding molecular or antigen template for validation with symptomatic individuals or individuals otherwise suspected of COVID-19 infection by their healthcare providers. For point-of-care, at-home, and over-the-counter tests, the FDA would consider authorizing tests with a positive percentage agreement (PPA) of at least 80% with 70% at the lower bound of the two-sided 95% confidence interval.
- Strategies for serial testing with less sensitive tests (i.e., PPA <80%) may be able to support authorization; however, clinical evaluation in an asymptomatic population would generally be expected before authorization of a screening claim, including for over-the-counter use, for such tests. Thus, where a much less sensitive test is proposed for authorization, more upfront validation data will be required.
- When the FDA authorizes a screening test for serial testing but the clinical validation data does not include any of the recommended total number of asymptomatic individuals, the FDA intends to include a “condition of authorization” in the letter of authorization that the developer conducts a study agreed upon with the FDA to establish performance with asymptomatic individuals within a specified timeframe. If this post-authorization study does not demonstrate adequate performance, the FDA would consider taking appropriate action such as revoking or revising the EUA.
