Reliability of Antigen Rapid Tests in Detecting Early Omicron Questioned

WASHINGTON — Beginning Jan. 15, private health insurers will be required to cover the cost of home testing kits despite recent concerns from elected officials and researchers over the reliability and availability of rapid antigen testing.

“I’ve heard from so many people who are waiting in long lines and going from pharmacy to pharmacy trying to find a test, or who are giving up on getting tested because tests are unavailable or cost too much,” Sen. Patty Murray, D-Wash., said Tuesday during a Senate hearing to discuss federal perspectives on COVID-19.

There are currently 16 authorized home diagnostic tests, which consist of 12 antigen tests and four molecular polymerase chain reaction, or PCR tests to detect a virus’ genetic material. 

Under the new White House policy, up to eight COVID home testing kits per month can be purchased through insurance for free, or an individual can submit a claim to an insurance provider for reimbursement. However, there are no monthly limits for how many PCR and rapid tests can be ordered by a health provider, which will also be fully covered by insurance.

The Biden administration expects 300 million tests to be available by February 2022. They hope to accomplish this by streamlining efforts of the FDA’s regulatory pathway to bring them into the US market.

While the tall order of rapid tests may help to address the current shortage of tests available on the market, there are new concerns about the reliability of antigen rapid tests in detecting early omicron infection.

The U.S. Food and Drug Administration made recent updates to their testing recommendations after reviewing preliminary evidence of antigen tests and patient samples of those infected with the omicron variant.

“Early data suggests that antigen tests do detect the omicron variant but may have reduced sensitivity,” said the FDA in the update. 

“Antigen tests are generally less sensitive and less likely to pick up very early infections compared to molecular tests,” the agency continues in the update.

The agency recommends that any individual who tests negative with an antigen test but suspect they have COVID-19 should follow-up with a molecular testing to determine if they have COVID-19 infection.

Researchers from Yale University also published recent findings that an at-home rapid antigen test may not be able to detect the omicron variant before infected people transmit it to others. 

“We need to reconsider our testing options. Testing strategies can’t just be a rigid thing. What applies for one variant doesn’t apply to others,” said Anne Wyllie, research scientist at Yale School of Public Health, in a phone call with The Well News. 

“These were observations made in early to mid-December, and we knew the country was relying on these tests to travel…what alarm bells do you ring?” questioned Wyllie.

“One needs to be sure that what we are seeing is an actual phenomenon, but knowing in the meantime the delay is going to cause continued spread,” continued Wyllie.

From Dec. 1- Dec. 31, Wyllie and researchers observed 30 fully vaccinated and boosted individuals in New York, Los Angeles, and San Francisco who were enrolled in employer testing programs requiring daily testing using both nasal rapid antigen tests and saliva PCR tests. 

The findings showed that during the initial days of infection while the PCR tests produced a positive result, all of the antigen tests reflected a false-negative result. 

According to the research, four of the infected individuals transmitted the virus to others before the rapid antigen test produced a positive result.

“There’s probably been hundreds or thousands of missed cases out there as the country relied on antigen tests to travel around the country during the holidays and see their families,” said Wyllie.

The study raises the issue with the reliability of rapid testing during the initial stages of infection but also points out potential issues that might occur with employer testing programs. 

“The policy implication is that rapid antigen tests may not be as fit-for-purpose in routine workplace screening to prevent asymptomatic spread of omicron, compared to prior variants,” said Wyllie.

The White House has also announced plans to launch a website that would make 500 million at-home tests available by mail, provide 50 million at-home tests to community health centers and rural clinics, and create surge testing sites.

However, Wyllie said that hopefully the need for rapid antigen saliva test or oral swab-based tests will be addressed as soon as possible. 

“I hope manufacturers of rapid antigen tests are actually going to do the responsible thing and validate the test for oral swabs. Otherwise, we just need more clear messaging from the likes of the CDC, from the White House, from anyone else in that position where they say you need to listen to symptoms and consider your exposures, and that if you had those you know you can’t always rely on that negative antigen test result,” said Wyllie.

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