Science

Frequent cheap rapid tests reduce Covid-19 viral load more effectively: Study

Prashasti Awasthi Mumbai | Updated on November 22, 2020 Published on November 22, 2020

The researchers found that test frequency and turnaround time is much more important than test sensitivity in preventing Covid-19 from spreading from asymptomatic patients.

Researchers speculated that testing half the population weekly by using inexpensive rapid COVID-19 tests would eliminate the virus within weeks even if those tests are not as accurate as gold-standard clinical tests.

The study was conducted by researchers at the University of Colorado Boulder and Harvard University and published in the journal Science Advances.

In the study, the researchers highlighted that such a strategy could lead to "personalized stay-at-home orders" without shutting down restaurants, bars, retail stores, and schools, the authors said.

"Our big picture finding is that, when it comes to public health, it's better to have a less sensitive test with results today than a more sensitive one with results tomorrow," said lead author Daniel Larremore, an assistant professor of computer science at CU Boulder.

He added: "Rather than telling everyone to stay home so you can be sure that one person who is sick doesn't spread it, we could give only the contagious people stay-at-home orders so everyone else can go about their lives."

 

Methodology

For the study, the researchers intended to explore whether test sensitivity, frequency, or turnaround time is pivotal to contain coronavirus.

The researchers also used mathematical modeling to forecast the significance of tests on three hypothetical scenarios: in 10,000 individuals; in a university-type setting of 20,000 people; and in a city of 8.4 million.

The researchers found through their hypothesis that frequency and turnaround time is much more important than test sensitivity.

But twice-weekly testing with a more sensitive PCR (polymerase chain reaction) test, which takes up to 48 hours to return results, reduced infectiousness by only 58 per cent.

The researchers further stated when the amount of testing was the same, the rapid test always reduced infectiousness better than the slower, more sensitive PCR test.

The reason behind the disparity is because around two-thirds of infected people are asymptomatic and as they await their results, they continue to spread the virus.

"This paper is one of the first to show we should worry less about test sensitivity and, when it comes to public health, prioritize frequency and turnaround," said senior co-author Roy Parker, director of the BioFrontiers Institute and a Howard Hughes Medical Institute investigator.

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Published on November 22, 2020
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