Explainers and Scientific Studies

Written By CDL Rapid Screening Consortium (Super Administrator)

Updated at April 30th, 2021

COVID-19 testing: One size does not fit all (Science)

To combat COVID-19, the “one-size-fits-all” approach that has dominated and confused decision-making with regard to testing and the evaluation of tests is unsuitable: Diagnostics, screening, and surveillance serve different purposes, demand distinct strategies, and require separate approval mechanisms. By supporting the innovation, approval, manufacturing, and distribution of simpler and cheaper screening and surveillance tools, it will be possible to more effectively limit the spread of COVID-19 and respond to future pandemics.

Screening testing of asymptomatic individuals to detect people who are likely infectious has been critically underused yet is one of the most promising tools to combat the COVID-19 pandemic (9). Infection with SARS-CoV-2 does not lead to symptoms in ∼20 to 40% of cases, and symptomatic disease is preceded by a presymptomatic incubation period (10). However, asymptomatic and presymptomatic cases are key contributors to virus spread, complicating our ability to break transmission chains (10).

Testing for SARS-CoV-2 [the virus that causes COVID-19] can be for personal or population health. Collection can be from symptomatic or asymptomatic individuals, as well as from wastewater and swabs of surfaces. The tests may be performed in central laboratories, at the POC, or using rapid tests. Attributes of tests differ according to application.

Testing for COVID-19: How to best use the various tests? (OECD Policy Responses to Coronavirus)

Rapid antigen tests have the main advantage of producing results much more quickly. They are also simple to use, can be performed at point-of-care, and are cheaper than molecular tests, allowing their use at very large scale. However, they are less reliable than molecular tests – they achieve good specificity but only moderate sensitivity.

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