More testing alone will not get us out of this pandemic

In the past few weeks, public-health experts were rightfully outraged at moves by the US Centers for Disease Control and Prevention (CDC) to discourage testing for asymptomatic people exposed to COVID-19. Expanding diagnostic testing is essential to inform public-health policies, education campaigns and containment strategies. But, as I’ve investigated testing approaches around the world, I worry that a narrow focus on more, and more-sophisticated, tests will divert attention from other crucial issues in testing and diagnosis.

Many governments are pinning their hopes on tests. The UK government plans to administer 500,000 tests daily by the end of October, more than double the current number; India’s Ministry of Health and Welfare has announced a goal of one million daily tests. Policymakers are also trying to innovate their way out of the problem: the US National Institutes of Health (NIH) has launched a US$1.5-billion funding initiative, Rapid Acceleration of Diagnostics (RADx), to do so.

Broader testing proffers a seductively straightforward technological remedy. But these solutions can fail when they run into messy, complex and unequal social realities.

Starting in April, the UK...