• Robert Preidt
• Posted June 26, 2020

Is 'Pooled' Coronavirus Testing the Next Step for America?

Large-scale "pooled" testing of Americans could curb the spread of the new coronavirus and allow most people to return to their normal lives within several weeks, a new report suggests.

The findings come as the White House coronavirus task force eyes the strategy as a potential solution to expand testing quickly across the country as cases surge in the South and Midwest.

Dr. Anthony Fauci told the Washington Post late Thursday that White House officials are having "intense discussions" about the new concept. On Friday, the coronavirus task force will hold a media briefing for the first time in nearly two months.

"When you are dealing with the kind of resurgences that we're seeing in certain locations -- and there is community spread which is clearly going on in a situation in which a substantial proportion of the infected people might be without symptoms -- the standard process of identification, isolation and contact tracing does not seem to be adequate," Fauci told the Post. "Therefore, we are seriously considering additional approaches, one of which is pooled testing.

"What you need to do is find the penetration of infected people in your society," Fauci told the Post. "And the only way you know that is by casting a broad net."

The pooled approach combines samples from multiple people at once, and would offer a way to minimize the number of tests needed, the New York Times reported. If the pooled sample comes back negative, everyone in the pool is considered to be virus-free.

If the sample comes back positive, each patient who provided a sample can then be tested individually. The strategy can be particularly effective when the prevalence of infection in a population is less than 30%, the Times reported.

Dr. Deborah Birx, the coronavirus task force response coordinator, told the American Society for Microbiology recently that "pooling would give us the capacity to go from a half a million tests a day to potentially 5 million individuals tested per day."

The method is already being used in Germany, Israel and several other countries, as well as in Nebraska and Tennessee, according to the Times.

In the pooled testing report, released as a white paper and not a published study, Cornell University researchers conducted a simulation of the pooled approach and concluded that if 1% of people have the coronavirus, this testing strategy could enable more than 90% of Americans to safely return to their daily routines within four weeks.

This group testing would entail 6 million tests a week -- far more than currently conducted -- but it's a feasible goal, according to simulation leader Peter Frazier, a researcher at Cornell.

"If we had the ability to provide tests to a large fraction of the population on a regular basis, that would allow us to find people who are infectious but don't know it, and then take action so that those people don't infect other people," Frazier said in a university news release.

"And one of our big challenges is we don't have the testing capacity to meet that need," he added.

In the simulation, the researchers presumed households would be tested once a week for four weeks, and household tests would be pooled in groups ranging from 41 samples to 62 samples.

Assuming a 30% false negative rate from improper swabbing and a 10% false positive rate, the simulation showed that by the end of four weeks, coronavirus prevalence would drop from 1% to 0.3% of the U.S. population.

"There's a trade-off -- if you don't have enough capacity to be able to test everyone with individual tests, then you can either test fewer people at less frequency with more accuracy, or you can sacrifice a little in terms of accuracy to test a large number of people at a greater frequency," Frazier explained.

More information

The U.S. Centers for Disease Control and Prevention has more on COVID-19.

SOURCES: Cornell University, news release, June 12, 2020; Washington Post; New York Times