The corona pandemic has had a significant impact on society and posed multiple challenges for national research systems to provide guidance to policy makers in the face of the rapidly changing global crisis situation. However, existing methods generally do not allow for an early and reliable assessment of how national research systems have reacted to a global crisis situation. We show how an expert-based, iterative classification scheme enables the analysis of research trends and country-specific differences at an early stage of the corona pandemic. In doing so, we have extended our focus beyond published research to the actions of research and technology organizations. In the European countries surveyed, a largely consistent but differentiated research landscape can be observed, with the focus shifting over time from medical and prevention-related topics to topics related to the social, environmental and economic impact of the crisis. However, there are country-specific differences, especially in research on social and mental issues, virus detection and diagnostics, and pandemic prevention measures. Thus, our approach provides a valuable framework that is applicable beyond COVID-19 and helps both researchers and policy makers to tackle rapidly evolving crises at an early stage. Our study contributes to existing literature by offering a comprehensive framework that goes beyond traditional publication dynamics, providing insights into the rapid response of national research systems during crises, such as the COVID-19 pandemic.