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FDA Releases Templates for SARS-CoV-2 Antibody Test Development

NEW YORK – Following on the heels of a template released on Tuesday for developers of tests for serial testing for COVID-19, the US Food and Drug Administration on Wednesday released two templates covering the development of serology tests for antibodies against SARS-CoV-2.

One new template is for developers of tests that detect or correlate to neutralizing antibodies against the coronavirus, while another template has been updated to include recommendations for monitoring and evaluating the impact of new SARS-CoV-2 mutations and variants.

Broadly, the templates contain information about the FDA's current recommendations concerning the data and information that should be submitted by test developers seeking Emergency Use Authorization for their SARS-CoV-2 antibody tests, as well as for pre-EUA submissions.

"The templates are intended to help test developers provide validation data and other information to the FDA, but alternative approaches can be used," the agency said, while reiterating tests for detecting antibodies against SARS-CoV-2 "should not be distributed and/or used to diagnose current infection."

Antibody-based tests were initially seen as one strategy to contain the spread of COVID-19 by using them for public health efforts to track SARS-CoV-2 infections and to monitor the prevalence of the virus in various communities. However, after the FDA said it would loosen its regulations for SARS-CoV-2 serology tests in March 2020, some used the tests to diagnose infections in specific individuals, against the recommendations of the agency. Additionally, tests of dubious quality began flooding the market.

Last month, officials from the FDA acknowledged errors were made by the agency in its handling of such tests.

On FDA's weekly town hall conference call on Wednesday with COVID-19 test developers, Tim Stenzel director of the FDA's Office of In Vitro Diagnostics and Radiological Health, addressed questions about the use of serology tests to assess the immune status of an individual who has received a vaccine for the disease. As more Americans become vaccinated, antibody tests have been discussed as a tool to evaluate whether a vaccine has conferred COVID-19 immunity to an individual. 

Stenzel said that may not be a good idea presently. Some clinicians have ordered a serology test for patients who had been vaccinated, he said, "and some of those test results are coming back negative, unexpectedly, and there is some concern.

"When investigations have been done, it turns out that that vaccine generates an antibody to a spike protein, but the serology test is directed toward the N protein. So, that serology test is obviously not going to be the ideal candidate for clinicians to order an off-label test to take a look at a response to vaccine," Stenzel said.

While the FDA remains open to additional claims around serology tests, "we want to make sure and expand upon what I just said about selecting the appropriate serology test to look for immune response from a vaccine. We will be looking at various pathways to do that and make sure that is clear to laboratories and clinicians."