Even with promising recent news on vaccine development, testing, tracking, tracing and isolating (TTTI) quickly and on a large scale continue to be essential to public health policy responses to the COVID‑19 pandemic. This note provides an update to an earlier OECD brief on such strategies in the light of recent developments in testing technologies. Molecular tests, and in particular RT-PCR, remain the reference for identifying infections because these tests are very reliable. But capacity constraints and the relatively high cost of RT-PCR limit its use on a massive scale. More recently-developed rapid antigen tests offer the advantage of producing results much more quickly. They are also cheaper, simple to use, and can be performed at point-of-care, thus allowing their use on a very large scale. However, they are less reliable than molecular tests. To achieve their objectives, testing strategies can combine different technologies and use them in complementary ways, taking into account their respective strengths and limitations.