Background
The COVID-19 pandemic demanded quick exchanges between experts and institutions supporting governments to provide evidence-based information in response to the crisis. Initially, there was no regular cross-country forum in the field of population health. This paper describes the set-up and benefits of implementing such a forum.

Methods
A group of public health practitioners from academia, national public health institutes and ministries of health decided in April 2020 to meet bi-monthly to discuss a vast array of population health topics in a structured format called a Rapid Exchange Forum (REF). An ad-hoc mailing group was established to collect responses to questions brought forward in the forum from at least five countries within 24 h. This endeavour, which evolved as network of networks was awarded an EU grant in autumn 2020 and was called PHIRI (Population Health Information Research Infrastructure).

Results
Responses from up to 31 countries were compiled and shared immediately via the European Health Information Portal. This exchange was complemented by special REFs that focused on the advantages and disadvantages of vaccination, for example. By July 2023, 54 REFs had taken place with topics going beyond COVID-19.

Conclusion
The REF demonstrated its value for quick yet evidence-based cross-country exchange in times of crisis and was highly appreciated by countries and European Commission. It demonstrated its sustainability even after the acute crisis by expanding the topics covered and managing to continue exchange with the aim of capacity building and mutual learning, making it a true EU response and coordination mechanism.