Illustration of man receiving a COVID test.
Illustration of man receiving a COVID test.

Opinion: What COVID-19 Has Taught Us About the Importance of Testing

The pandemic has yielded many lessons. One is that adequate and well-distributed diagnostics are key to battling disease outbreaks.

A photograph of Mark Kessel
Mark Kessel

Mark Kessel is chairman of FIND, the global alliance for diagnostics.

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Feb 1, 2022


The number of cases of COVID-19 has exceeded 250 million globally and at least 5 million people have died as a result of infection by SARS-CoV-2, with many organizations believing these to be underestimates. It is now clear that the devastating impact of this pathogen on world health and economies could have been mitigated if certain missteps had been avoided, particularly when it came to testing. 

As we have seen with COVID-19—and in the past with SARS, Ebola, Zika, and MERS—outbreaks must be quickly identified in order to be contained. Testing is the front line of global health surveillance, providing warning of potential outbreaks so that health officials can rapidly seek to slow or stop their spread. But to do this, we need diagnostics that can identify pathogens that have high outbreak potential. Currently, no approved diagnostic test exists for 60 percent of the Blueprint pathogens identified by the World Health Organization (WHO) as having the greatest outbreak potential. 

Without adequate testing tools, the likelihood of future pandemic pathogens emerging, especially in low- and middle-income countries (LMICs) where infectious diseases are frequently underdiagnosed, is high. The global health community must provide adequate funding for the development of diagnostics and access to these tests around the world, including in LMICs. As diagnostics constitute a very small proportion of overall healthcare costs, yet drive about 70 percent of healthcare decisions, such investments could have substantial impact.

We must learn from the lessons that COVID-19 has taught us in order to better manage future disease outbreaks and prevent further unnecessary loss of life.

But testing on the leading edge of an outbreak is only part of the utility of robust diagnostics. With COVID-19, the world has witnessed unprecedented vaccine development in less than 12 months. This result could not have been achieved without diagnostic tests to assess whether vaccines are effective in protecting people in clinical trials and real-world settings. But once vaccines began to roll out, some countries moved away from testing, placing it on the back-burner and relying solely on the vaccines to slow the spread of disease. That was a mistake.

Neither vaccine coverage nor vaccine efficacy against existing and emerging variants of COVID-19 is 100 percent. With vaccine resistance and hesitancy still widespread in many countries, affordable on-the-spot testing can help keep people safe in schools, workplaces, and home care, and can enable airline travel to be restored to pre-pandemic levels. Some countries have taken this approach one step further, with extensive testing used to implement a “zero-COVID” strategy, aiming to eliminate COVID-19 entirely within mainland borders. While Australia, New Zealand, and Singapore are now relaxing this policy, China has stuck to it, and was able to limit the spread of the Delta variant last year. Testing therefore continues to be an essential tool in providing safe environments in the workplace and beyond, and will become increasingly important in the face of emerging variants of SARS-CoV-2 and novel pathogens that are almost certain to circulate in the future.

Testing to address all of these concerns would benefit from further technological development. The current gold standard diagnostic for COVID-19 is a reverse transcriptase polymerase chain reaction (PCR) test. Such tests, which use samples collected with nasal or throat swabs, tend to require trained personnel, expensive machines, and specific reagents, and can take days to produce results due to backlogs at testing facilities. The high cost of PCR testing also limits the coverage that can be achieved. Through the course of the pandemic, it became clear that these tests were not suitable for controlling the spread of COVID-19. To slow transmission in real-world settings, simpler, faster, more-accessible, and more-affordable tests were needed.

To meet this need, numerous companies developed COVID-19 rapid antigen tests, which were ready for deployment within eight months of the initial outbreak—another world record. These tests are also taken with a nasal or throat swab to identify a protein that is part of the coronavirus, but they are faster and much less expensive than PCR tests, usually around US $3 in LMICs at the moment. Although they are slightly less accurate than PCR tests, they are effective in identifying infective individuals with high viral loads, and are useful tools to stem pandemics. Antigen tests were widely implemented in high-income countries, but regretfully, some governments adopted nationalistic policies, hoarding these tests for their own citizens. From a world health perspective, such policies only fueled the pandemic, especially in LMICs, where diagnostic capacity is already poor. 

Global access to sound testing technologies and strategies is essential in the face of a pandemic, and cooperation between nations is the only way to achieve this goal. One of the more successful efforts to address the pandemic was the Access to COVID-19 Tools (ACT) Accelerator, a collaboration between governments, scientists, businesses, civil society, philanthropists, and global health organizations to foster the development, production, and equitable distribution of COVID-19 tests, treatments, and vaccines. While the funding received for testing was not as robust as the ACT Accelerator members had hoped for, significant achievements to date have included halving the cost of rapid antigen tests, independently evaluating the performance of commercially available tests, and training more than 42,000 healthcare workers across nearly 200 countries to administer tests. The ACT consortium—which includes FIND, the global alliance for diagnostics, where I am chairman—announced in November an investment of $50 million to support scale-up of testing and treatment packages in LMICs that currently have insufficient diagnostic capacity and lack lifesaving therapies.

The global community has failed at times to make the best use of diagnostics to address COVID-19. Politicization of testing and overreliance on vaccines has likely extended the duration of the pandemic. Additionally, despite the fact that pathogens do not respect national boundaries, especially in an interconnected world, LMICs have suffered disproportionately from the impact of test hoarding by high-income countries, as well as from an existing overall lack of diagnostic capacity. Although cooperative efforts have helped to address some testing gaps, we must learn from the lessons that COVID-19 has taught us in order to better manage future disease outbreaks and prevent further loss of life.

Mark Kessel is the chairman of the board of directors at FIND, the global alliance for diagnostics.

This article was featured in February 2022, Issue 1 of the digest