FDA OKs COVID-19 rapid test; CDC talks testing guidance

SARS-CoV-2 rapid test
SARS-CoV-2 rapid test

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The US Food and Drug Administration (FDA) has granted an emergency use authorization (EUA) for a rapid COVID-19 test developed by Abbott Laboratories.

This is the first antigen test that can be read from a testing card, similar to a home pregnancy test. The test costs $5, and results take about 15 minutes.

"This new COVID-19 antigen test is an important addition to available tests because the results can be read in minutes, right off the testing card. This means people will know if they have the virus in almost real-time," said Jeff Shuren, MD, JD, director of the FDA's Center for Devices and Radiological Health, in an FDA press release.

Yesterday, Abbott said it plans to ship tens of millions of the tests in September and increase production to 50 million tests in October.

Expert warns of low sensitivity of rapid tests

Antigen tests, as opposed to molecular tests, are very specific but not as sensitive. The FDA said a negative test result from the new test may need to be confirmed with a molecular test before making treatment decisions. Abbott has said the test, BinaxNOW COVID-19 Ag Card, picks up 97% of positive cases.

But Michael T. Osterholm, PhD, MPH, director of the University of Minnesota's Center for Infectious Disease Research and Policy, which publishes CIDRAP News, warned that the 97% figure came from a collection of just 102 samples, according to information from the FDA.

"The entire sensitivity is based on 102 samples and only 35 positives," said Osterholm. "This test might be used as a surveillance test, but there's no way it can be used as a diagnostic test."

He also said there's no reason to think the test will perform any better than Abbott's BinaxNow influenza A and B test, another rapid antigen test. "That test is not recommended because it has a 50% to 70% sensitivity," said Osterholm.

Redfield addresses testing guidance amid criticism

In other testing news, Centers for Disease Control and Prevention (CDC) Director Robert Redfield, MD, addressed new guidance on the CDC’s website that suggests that asymptomatic contacts of COVID-19 cases may not need to be tested for the virus.

According to the New York Times, Redfield issued a statement last night that "testing may be considered for all close contacts of confirmed or probable COVID-19 patients," but the CDC is "placing an emphasis on testing individuals with symptomatic illness, individuals with a significant exposure, vulnerable populations including nursing homes or long term care facilities, critical infrastructure workers, healthcare workers and first responders, or those individuals who may be asymptomatic when prioritized by medical and public health officials."

Yesterday, Admiral Brett Giroir, MD, the US testing czar, said that he and Redfield—not the White House—changed the guidance and that it was meant to prevent people with negative test results from having a false sense of security.

Following the CDC's change to recommendations earlier this week, three Democratic governors (Andrew Cuomo of New York, Jay Inslee of Washington, and Gavin Newsom of California) said they would not follow the guidelines and still recommend testing for all case contacts.

The Infectious Diseases Society of America and the HIV Medicine Association and the American Medical Association (AMA) also released statements on the CDC guidelines, criticizing the change.

"Months into this pandemic, we know COVID-19 is spread by asymptomatic people. Suggesting that people without symptoms, who have known exposure to COVID-positive individuals, do not need testing is a recipe for community spread and more spikes in coronavirus," said Susan Bailey, MD, president of the AMA, in a press release.  "When the Centers for Disease Control and Prevention (CDC) updates a guidance the agency should provide a rationale for the change."

Other US developments

  • The United States reported 44,109 new COVID-19 cases yesterday, and 1,222 deaths, according to the Johns Hopkins COVID-19 tracker. The total now stands at 5,856,014 cases and 180,468 deaths.

  • The Biomedical Advanced Research and Development Authority (BARDA) is investing $2.5 million into the development of needle-free COVID-19 vaccines.

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