Fact check: Inventor of method used to test for COVID-19 didn’t say it can’t be used in virus detection

Correction Nov. 13, 2020: The verdict of this fact check has been changed from false to misleading, to reflect that the quote examined may have been a fair reflection of Mullis’s views, even if not a direct quote. The body of the text is updated in places to further clarify this.

Reuters Fact Check. REUTERS/Axel Schmidt


Social media users have been sharing a quote attributed to the inventor of the Polymerase Chain Reaction (PCR) test, currently being used to detect COVID-19, which says “PCR tests cannot detect free infectious viruses at all”. This quote appears not to be a direct quote from the inventor, Kary Mullis, has lost some context and does not mean COVID-19 testing is fraudulent, as suggested by some social media posts.

The posts have been shared over 1,000 times on Facebook (herehere  ,  here).

The post begins with the words “COVID-19 TEST a FRAUD?”, then introduces the alleged quote from Mullis, who invented the PCR method in 1985 and was recognized for this achievement by being awarded the Nobel Prize in Chemistry in 1993 (here).

However, the quote is actually from an article written by John Lauritsen in December 1996 about HIV and AIDS, not COVID-19 (here).

The context around the quote shows Lauritsen is not saying PCR tests do not work. Instead, he is clarifying that PCR identifies substances qualitatively not quantitatively, detecting the genetic sequences of viruses, but not the viruses themselves: “PCR is intended to identify substances qualitatively, but by its very nature is unsuited for estimating numbers. Although there is a common misimpression that the viral load tests actually count the number of viruses in the blood, these tests cannot detect free, infectious viruses at all; they can only detect proteins that are believed, in some cases wrongly, to be unique to HIV. The tests can detect genetic sequences of viruses, but not viruses themselves.”

Even if Mullis had voiced a similar statement before his death in 2019, this quote does not mean the PCR test is unable to detect the presence of SARS-CoV-2 - the virus that causes COVID-19 - rather that it cannot determine whether the individual tested is infectious.

The PCR test is the preferred COVID-19 testing method in England ( It detects the presence of the virus by amplifying the virus’genetic material to a point where it can be detected by scientists (

A spokesperson for Public Health England told Reuters why PCR tests are being used widely in England: “Molecular diagnostic tests, such as real-time PCR, are the gold standard methods for identifying individuals with an active viral infection, such as SARS-CoV-2 (the cause of COVID-19 disease), in their respiratory tract. These tests are rapid and produce results in real-time.

“It is important to note that detecting viral material by PCR does not indicate that the virus is fully intact and infectious, i.e. able to cause infection in other people. The isolation of infectious virus from positive individuals requires virus culture methods. These methods can only be conducted in laboratories with specialist containment facilities and are time consuming and complex.”


Misleading. The quote regarding the limitations of PCR tests appears not to be directly from Mullis, but in any case is not evidence the test is fraudulent. PCR tests are being used widely in England to show that SARS-CoV-2 viral genetic material is present in the patient.

This article was produced by the Reuters Fact Check team. Read more about our work to fact-check social media posts here .