The research question of this study is: "what lessons have been learned from the civil-military cooperation in Heidelberg, Germany, during the COVID-19 pandemic, and what needs to be done to be better prepared for future disasters?" It is expected that the results of this research provide a deep expert insight into COVID-19 disaster preparedness at the local level. Flanked by comparison with published experiences at the global level, these lessons-learned would contribute to strengthening local crisis resilience sustainably in the future.

Design, execution, analysis and publication of this study is conducted in compliance with the international quality criteria "STrengthening the Reporting of OBservational studies in Epidemiology (STROBE)" and "Standards for Reporting Qualitative Research (SRQR)".

This is a monocentric, qualitative, mixed-methods, non-interventional, non-randomized research project.

Inclusion Criteria:

1. Age over 18 years
2. Direct or indirect involvement in civil-military collaboration during the COVID-19 crisis
3. Ability to provide consent
4. Providing written informed consent to participate in the study

Exclusion Criteria:

1) Failure to provide written informed consent to participate in the study

Key stakeholders of the local disaster relief community