Lessons from COVID-19 for improving diagnostic access in future pandemics.

Throughout the COVID-19 pandemic, we have witnessed the critical and expanding roles of testing. Despite the development of over a thousand brand of tests - with some close to fulfilling the 4As (accuracy, access, affordability, and actionability via quick time to result) of an ideal diagnostic test - gaps persisted in developing tests to fit public health needs, and in providing equitable access. Here, we review how the use cases for testing evolved over the course of the COVID-19 pandemic, with associated engineering challenges (and potential lessons) at each phase for test developers. We summarise lessons learnt from the recent epidemic and propose four areas for future cooperative effort among test developers, government regulators and policy makers, public health experts, and the public: 1) develop new models for public sector funding and research and development; 2) increase testing capacity by investing in adaptable open-platform technologies at every level of the healthcare system; 3) build data connectivity infrastructures to support a connected diagnostic system as a backbone for surveillance; and 4) facilitate the rapid translation of innovation into use through a coordinated framework for regulatory approval and policy development.