Fact check: COVID-19 PCR test created to detect infection, not vaccinate

Chiara Vercellone, USA TODAY
·6 min read

The claim: PCR tests weren't designed to diagnose illness, are vaccines in disguise

While they've been the gold standard to identify positive coronavirus cases around the world for more than a year, PCR tests still aren't trusted by some social media users.

An Oct. 4 Instagram post is propagating misinformation about the molecular tests, claiming they weren't created to be a diagnostic tool and implying they could be COVID-19 vaccines in disguise.

"The PCR test was never designed to diagnose illness," reads text in an image that was liked more than 200 times in one day.

The post includes photos of kids and adults being tested for COVID-19 with a nasal swab, the traditional way a PCR test is performed. Accompanying those is an image of a cow receiving a nasal swab, captioned, "How farm animals are vx'd"

Fact check: Misleading claim that Norway has 'reclassified' danger of COVID-19

PCR tests have been around since the 1980s, used extensively throughout medicine and biology due to their ability to accurately detect illness. But that's all they do.

PCR tests don't contain vaccines. Efforts to create a COVID-19 vaccine administered via nasal swab are underway, but no such vaccine is yet approved for use.

USA TODAY reached out to the poster for comment.

PCR test diagnoses infection, isn't a vaccine

This is not the first time misinformation has arisen about PCR tests. USA TODAY has debunked misleading or false claims that PCR tests don't detect different coronavirus strains and that multiple tests are required to ensure a positive result.

Now the claim is that PCR tests aren't only a diagnostic tool – a concept some commenters were quick to get behind.

"Annnnd this is why my family and I will NEVER EVER allow them to swab us!" one wrote. "Saliva testing ONLY if u (sic) must be tested!"

Another commented, "I hope I was only tested."

Richard Martinello, an associate professor of medicine and infectious diseases at Yale University, said there's no way the PCR test is a vaccine in disguise.

"Of course, there's no substance to this theory," said Martinello, who specializes in the transmission and prevention of respiratory viruses. "While we do have an FDA-approved nasal influenza vaccine, it is provided as a liquid which is sprayed into the recipient’s nostrils. The swabs used for specimen collection are dry. "

The swabs used for testing are all sterile and removed from the packaging "just before use, and they come from multiple manufacturers," Martinello said in an email to USA TODAY.

Vaccines administered through the nose are not unheard of, however. Since 2003, Americans have been able to choose if they want their flu vaccine in the form of a nasal spray-like vaccine administered by a health care professional.

But there isn't an approved or authorized intranasal vaccine for COVID-19.

The biotechnology company Meissa released preclinical data in July from its intranasal vaccine that showed a single dose administered to nonhuman primates "provided equivalent protection" against COVID-19 compared to the then-authorized vaccines.

The company announced it had enrolled adults in a Phase 1 trial and that an analysis of the data was expected to be available later this year.

Fact check: Facebook outage caused by human error, not a military raid

Fact check: Southwest Airlines, union deny rumor that pilot sickout caused flight delays

PCR tests, as well as many other infection-diagnosing tests, are done through nasal swabs because that's what medical experts have relied on for decades to diagnose an upper respiratory virus, Martinello said.

"The overwhelming bulk of experience worldwide has been with the use of nasal specimens, so we still rely on nasal specimens," he said.

Saliva tests can be used as well, though Martinello said the usage is limited since fewer labs are set up to process those.

Saliva samples have been found to be a successful and accurate way of testing for COVID-19, according to Martinello. The Food and Drug Administration has authorized (under emergency use authorizations) various tests capable of identifying an active COVID-19 infection through saliva samples, including one developed at Yale University.

Fact check: Merck's molnupiravir and ivermectin are not the same drug

Nasal vaccines used for cows

There was another claim in the Instagram post: that cows get vaccinated through the snout. That's accurate.

Some cattle vaccinations are sold as intranasal vaccines. For example, Bovilis INtranasal RSP, which protects the cow against respiratory diseases, can be administered directly from the syringe into the nostril or with a mist applicator similar to a nasal spray, according to the manufacturer's website.

Cows also are tested for disease through nasal swabs, however, according to the Wisconsin Veterinary Diagnostic Laboratory at the University of Wisconsin-Madison. So it's not clear which action is shown in the picture in the post. USA TODAY didn't find where the image being shared on social media originated.

Fact check: Flu cases declined during 2020-2021 season compared to previous years – but not by 379M

How a PCR test works

PCR tests are a "highly accurate" way to quickly diagnose certain infectious diseases like COVID-19 and Ebola, according to the National Library of Medicine at the National Institutes of Health.

The three-letter acronym now recognized by most people stands for "polymerase chain reaction," which is a technique used to copy and multiply small segments of DNA for further research, according to the National Human Genome Research Institute.

The technique is crucial in nearly every DNA study and analysis because these require "significant" amounts of DNA samples, which PCR facilitates. Since the test copies the genetic material in a sample multiple times, it can easily identify a pathogen causing the disease or abnormal cells in the earliest stages of infection, the national medicine library said.

The COVID-19 RT-PCR test was created by the Centers for Disease Control and Prevention in February 2020 to specifically diagnose coronavirus-positive cases in the country.

Fact check: Video of Dr. Anthony Fauci saying he wouldn't get COVID-19 test is outdated

PCR tests work best to identify an active infection, unlike antibody tests, which can tell if you've been infected in the past.

Fact check: No, the CDC didn't warn of a polio-like disease outbreak coming in 2021

Fact check: Gas sterilization of COVID-19 test swabs is safe, won't cause cancer

Our rating: False

Based on our research, we rate FALSE the claim that PCR tests weren't designed to diagnose illness and that they are disguised vaccines. The current PCR test used to detect COVID-19 was created by the CDC in February 2020 to diagnose active cases of the virus across the country. The claim that they are vaccines has no substance, experts told USA TODAY. No intranasal COVID-19 vaccines have been authorized, though the concept is being studied.

Our fact-check sources:

Thank you for supporting our journalism. You can subscribe to our print edition, ad-free app or electronic newspaper replica here.

Our fact-check work is supported in part by a grant from Facebook.

This article originally appeared on USA TODAY: Fact check: PCR coronavirus test effective in diagnosing infection