Welcome to the Imperial College London Science Matters, Let's Talk series exploring the coronavirus disease (COVID-19) epidemic. On January 30th, the World Health Organisation (WHO) declared the outbreak of COVID-19 (previously termed 'novel coronavirus' or '2019-nCoV'), a public health emergency of international concern. COVID-19 is caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which is sometimes also referred to as the COVID-19 virus. As the epidemic seems to spread to more and more countries, people around the world are wondering about the trajectory of the epidemic and whether they should be concerned. Media reports of the epidemic often focus on the more eye-catching events: governments evacuating their citizens from Hubei province, passengers on cruise ships being stopped from disembarking following a detection of a case, or images of supermarket supplies running out in areas perceived to be at high risk. On social media, other reports about the epidemic range from unsupported rumours to deliberate disinformation are increasing a sense of panic many individuals are experiencing. Robust, reliable analysis is vital at this stage not only as a way to give concerned members of the public a sense of perspective, but also to support governments and other stakeholders in planning their responses. Researchers at the MRC Centre of Global Infectious Diseases Analysis (GIDA) and the Jameel Institute for Disease Emergency Analytics (J-IDEA) have been working hard on coming up with reliable estimates of the spread of the epidemic and its prospects, and are doing this in close collaboration with a number of global stakeholders, including the World Health Organisation (WHO). You will hear directly from the experts conducting the analyses. You will be able learn about the current state of the epidemic, while also learn about the epidemiological and public-health principles and challenges that underpin these analyses. This will include understanding how the spread of the epidemic is modelled, how transmissibility of infections is estimated, what the challenges are in estimating the case fatality ratio, and also learning about the importance of community involvement in responding to the epidemic. If you want to learn more about infectious disease modelling, epidemiology, participatory approaches in public health, or health economics, a number of free MOOCs are available from Imperial College London. We also offer a fully online Global Master of Public Health for those of you who want to delve even deeper, as well as free online open courses. Follow this link to find out more about the courses we offer: https://www.coursera.org/collections/open-courses-global-mph-imperial Follow this link to find out more about work being done at J-IDEA: https://www.imperial.ac.uk/jameel-institute/ Please note that we are creating all the content in real time, and new material will be uploaded as it becomes available.