An alert from the Centers for Disease Control and Prevention (CDC) in America announcing that it will withdraw the request for emergency authorisation of a PCR test has been widely shared on social media in the UK, and claimed to be evidence that the tests have “failed their full review”, and that PCR tests are “meaningless”, “fraudulent”, “not fit for purpose”, or unable to distinguish between influenza and Covid-19. This is not true.
The alert said: “After December 31, 2021, CDC will withdraw the request to the U.S. Food and Drug Administration (FDA) for Emergency Use Authorization (EUA) of the CDC 2019-Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel”.
The Department of Health and Social Care told Full Fact that it does not use the CDC test in question.
Emergency use authorisation allows the FDA to authorise the use of unapproved medical products or new uses of approved medical products required in an emergency (like the pandemic) in America, when certain criteria are met.
In addition, the alert said that the CDC encourages laboratories to consider using other PCR tests which can test for both influenza and SARS-CoV-2.
A CDC spokesperson told Full Fact that the PCR test in question—the CDC Novel Coronavirus (2019 nCoV) Real-Time RT-PCR—is “a highly accurate test” and the decision to discontinue the request for emergency use authorisation was not due to performance issues.
They explained that since this type of PCR test was introduced, more PCR tests have become available from commercial manufacturers.
These are “faster, have higher throughput [quicker processing] and are designed to be more efficient” and mean demand for the CDC’s PCR test has “declined significantly”.
The CDC said it is encouraging public health labs to adopt the CDC Influenza SARS-CoV-2 (Flu SC2) Multiplex assay, which allows simultaneous testing for both influenza and SARS-Cov-2 (the virus which causes Covid-19).
The CDC Influenza SARS-CoV-2 (Flu SC2) Multiplex Assay, is still a type of PCR test, but rather than individuals having to be tested for Covid-19 and then other respiratory viruses, this test involves taking one sample which can then be simultaneously tested for influenza and SARS-CoV-2. There are many other PCR tests which have been, and continue to be, approved by the FDA for Covid-19 testing.
This does not mean that other PCR tests cannot distinguish between SARS-CoV-2 and influenza. Covid-19 PCR tests are very accurate tests, and are specific for the SARS-CoV-2 virus because they detect the presence of its genetic material. Like all tests they will have a small number of false positives and false negatives, but they will not accidentally misinterpret the presence of other viruses such as influenza for SARS-CoV-2. We have written about this before.
The FDA told Full Fact that at present, the emergency use authorisation for the CDC 2019-nCoV RT-PCR Diagnostic Panel is still in effect. The spokesperson also clarified that this was a voluntary withdrawal on behalf of the CDC rather than any restriction or withdrawal being imposed by the FDA. Therefore, claims which say that the test failed its full review are untrue.