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COVID-19 variants tested through genome sequencing

July 28, 2021 GMT

CLAIM: No test can identify COVID-19 variants. Tests can only determine if a person is positive or negative for the disease.

AP’S ASSESSMENT: False. Variants can be tested through genome sequencing, which can take place after a COVID-19 test comes back positive.

THE FACTS: Social media users are taking advantage of the growing concern around the COVID-19 delta variant to push out misinformation online.

Recent posts are claiming that health professionals are lying to patients about contracting the variant and that a test for it does not exist.

One of the diagnostic tests for COVID-19 is the polymerase chain reaction or PCR test, which can identify about three locations within the genome of the virus, said Dr. Phil Febbo, chief medical officer for Illumina, a San Diego-based company that develops genomic sequencing technologies.

In order to test for variants, some tests undergo full genome sequencing to see how the virus has evolved since its origins.

“It’s the patterns of mutations in the genome that determine the differences,” Febbo said of the variants.

Viruses mutate or change as they spread, creating variants. Variants can make a virus more transmissible or lead to more severe disease. Repositories online allow medical officials to scan and see all the different sequences of the virus.

Researchers sequence viruses to answer such questions as whether a given variant is more or less dangerous and whether it increases risk for people, said Dr. Angela Branche, co-director of the University of Rochester Vaccine Treatment Evaluation Unit.

“It’s meant to help us understand how quickly the virus changes itself and the current protection you get after you are infected,” Branche said.

The delta variant was first detected in India and now makes up 83% of U.S. COVID-19 cases.

“We have seen cases skyrocket in the last few weeks. The vast majority of that is attributable to SARS-COV2 delta variant because we are sequencing a good chunk of all positive cases across the country,” said Joseph Fauver, associate research scientist in epidemiology at the Yale School of Public Health.


This is part of The Associated Press’ ongoing effort to address widely shared misinformation, including work with Facebook and other platforms to add context to misleading content and reduce its circulation online.

Here’s more information on Facebook’s fact-checking program: