Several social media posts attributing to article published on an American conservative website called The Gateway Pundit has gone viral that claims the US Centres of Disease Control and Prevention (CDC) has withdrawn the PCR tests as it could not distinguish between the influenza and the novel coronavirus.
The claim goes on to say that this was the reason for the "disappearance of flu cases in the US in 2020".
However, we found that the claim was false. In July 2021, CDC did say that it would withdraw the request for the emergency use authorisation for it's PCR test after 31 Dec, but it had nothing to do with the flu. As per a clarification posted by the CDC, the reason for withdrawal was that the FDA has now authorised several other COVID-specific tests and the CDC's test was no longer "filling an unmet need".
Moreover, experts have also said that it is not possible for the COVID PCR tests to get confused with the flu virus.
The headline of the article on The Gateway Pundit said, "HUGE. CDC Withdraws Use of PCR Test for COVID and Finally Admits the Test Can Not Differentiate Between the Flu and COVID Virus".
Social media users who shared the claim copied the text from the article.
WHAT WE FOUND OUT
The article in the website referred to a "Laboratory Alert" published by the CDC on 21 July 2021.
The alert said, "After December 31, 2021, CDC will withdraw the request to the US 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 assay first introduced in February 2020 for detection of SARS-CoV-2 only. CDC is providing this advance notice for clinical laboratories to have adequate time to select and implement one of the many FDA-authorised alternatives."
"CDC encourages laboratories to consider adoption of a multiplexed method that can facilitate detection and differentiation of SARS-CoV-2 and influenza viruses. Such assays can facilitate continued testing for both influenza and SARS-CoV-2 and can save both time and resources as we head into influenza season," the alert said.
The alert didn't say that the PCR tests were unable to distinguish or differentiate between the flu and COVID-19.
WHY DID CDC WITHDRAW THE EUA REQUEST?
It is standard practice for the US Food and Drug Administration to issue temporary EUA to tests, devices and drugs that have not gone through the full approval process in case of an emergency - such as the COVID-19 pandemic.
In February 2020, the FDA granted EUA to the CDC’s 2019-nCoV RT-PCR test. At that point no other tests were available to detect the novel coronavirus.
However, since then the FDA has authorised several other SARS-CoV-2 diagnostic tests, some of which have higher accuracy and the ability to test more than one illness at a time. That was the reason behind retiring the test developed by CDC.
The CDC issued a clarification on the previous published "Lab Alert" on 2 August 2021 where it clarified that the withdrawal of the EUA was only meant for the CDC’s 2019-nCoV RT-PCR test and not the other tests approved by the FDA.
It also clarified that there were no performance issues with the test and it didn't fail the full review.
"The CDC 2019-nCoV Real-Time RT-PCR Diagnostic Panel does not confuse influenza with SARS-CoV-2. It is a highly accurate test that detects the presence or absence of SARS-CoV-2 viral genetic material within a patient specimen," the clarification also said.
CDC also said that the probes and primers for the first PCR test will be publicly available on the CDC website for the reference of labratories and test developers.
The clarification also added that the CDC Influenza SARS-CoV-2 (Flu SC2) Multiplex Assay, which recieved FDA EUA in July 2020, will still be available. This test is able to simultaneously check for the presence of COVID-19 and the flu, thus saving time and resources that might have been needed in conducting separate tests.
Finally, the clarification mentions that the COVID-19 PCR tests can't detect flu as the genetic material used in such tests are different.
"The CDC 2019 Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel was specifically designed to only detect SARS-CoV-2 viral genetic material," it said.
DID FLU "DISAPPEAR" IN THE US in 2020?
The claim also stated that the flu, caused by the influenza viruses, had disappeared in the US in 2020, refering to a debunked conspiracy theory that COVID-19 is "just like" the flu.
While CDC has noted a fall in the number of flu cases in 2020-21, the organisation said that COVID-19 measures such as "wearing face masks, staying home, hand washing, school closures, reduced travel, increased ventilation of indoor spaces, and physical distancing, likely contributed to the decline".
Additionally, while there are some similarities between the symptoms of COVID-19 and flu, there are some big differences. For instance, COVID-19 is more contagious than the flu and it caused more serious illnesses in some people that resulting in hospitalisations and deaths.
Researchers in the Department of Immunology and Infectious Diseases at Harvard found that the reason for reduction in cases of flu was because COVID-19 was more contagious.