Viral Posts Misrepresent CDC Announcement on COVID-19 PCR Test -
8 min read
Scientists consider polymerase chain reaction, or PCR, tests a highly reliable tool for diagnosing COVID-19. But social media posts are misrepresenting a recent Centers for Disease Control and Prevention announcement regarding the eventual discontinuation of its own test, falsely claiming the government has conceded that PCR tests aren't reliable.
SciCheck Digest

What tests are available for COVID-19? What tests are available for COVID-19?

Tests that detect current infections with SARS-CoV-2, the virus that causes COVID-19, are known as viral tests. There are two types: a Nucleic Acid Amplification Test, or NAAT, and an antigen test. Many of the NAATs use a molecular biology technique known as the polymerase chain reaction, or PCR, to detect even a very tiny amount of the virus in a specimen. The PCR test takes advantage of some natural features of biology to essentially scan through all of the RNA present in a sample — such as a nasal swab — and search for the presence of coronavirus RNA. The Centers for Disease Control and Prevention says NAATs "are unlikely to return a false-negative result of SARS-CoV-2," and it recommends only laboratory-based NAATS, the most sensitive tests, to confirm infection. It also says saliva tests aren't as optimal as those using swabs of the nose or nasopharynx (upper throat behind the nose). An antigen test is designed to detect the coronavirus antigen, a structure on the surface of the virus that triggers an immune response. Also conducted via a nasal or throat swab, antigen tests are less sensitive than NAATs but inexpensive and can usually produce results in about 15 minutes. Getting a result from a NAAT test can take about an hour or even a few days. Testing can help stop the spread of the coronavirus from those who test positive, because they can then isolate themselves from others. But, as we've explained, testing has its limitations. It can take a few days or even longer after exposure to the virus before it's detectable by the diagnostic tests. So even some with negative results could be infectious. Still, to help limit the spread, the U.S. has instituted travel requirements and recommendations. All international airline passengers, including U.S. citizens and residents, and those who are fully vaccinated, arriving in the U.S. must show "a negative COVID-19 test,…
Angelo Fichera
Read full article