Apr 28 2021 Read 20 Times Testing has played a critical role in helping to slow the spread of COVID-19 in countries around the world. Since the outbreak was declared a pandemic by the World Health Organization (WHO) in early March 2020, hundreds of millions of tests have been carried out. The US alone has performed almost 400 million tests, with India, China, the United Kingdom and Russia also recording huge numbers. Like the global approach to coronavirus, testing has evolved significantly over the past year. Below, we take a look at how testing has changed since the first cases of COVID-19 were detected in late 2019.