White House Outbreak Is Not a Failure of Testing
Guarding against Covid-19 requires a layered defense
The Covid-19 tests that involve shoving a swab up the nose, so-called PCR tests, are not only uncomfortable but involve a frustrating lag for lab work to provide results. At the White House, where things move fast and lots of people come and go, there was a great need for a much quicker approach to ensure people are Covid-free before entering meetings or, say, attending the September 26 ceremony for Supreme Court nominee Amy Coney Barrett.
Enter rapid testing.
The White House has been using a portable rapid test created by Abbott Laboratories. It returns results in 15 minutes without the need for lab technicians. The Abbott test, called an antigen test, was approved by the Food and Drug Administration in late August for emergency use. (Several other rapid Covid-19 tests are being developed by multiple companies.)
Abbott’s rapid test “has not been independently evaluated for accuracy and reliability,” according to Kaiser Health News. But it is thought to work well for its intended use. We’ll get to that in a moment.
“I think it’s a great test,” said Michael Mina, MD, an assistant professor of epidemiology at Harvard T.H. Chan School of Public Health who has been a leading promoter of the value of rapid coronavirus tests in a recent reporter call. “It works really well, it’s probably the best rapid test that we have available. And so they’re using it [in the White House]. And it’s a good call.”
But rapid tests have an important limitation. They can accurately detect Covid-19 once a person has symptoms and is highly infectious, but unlike PCR tests, they are not sensitive enough to detect most infections earlier on, when a person has a relatively small amount of the virus, or does not have symptoms but could be infectious.
In short: Rapid tests produce a high rate of false negatives.
For people who aren’t interacting with dozens or hundreds of other people every day, doing rapid tests at home a couple times a week could, across a population, identify far more Covid-19 cases, and many of them sooner, than happens now. While a person might be two or three days into an infection before…