Acknowledgments
The authors would like to thank the Health Department and Department of Education of the Government of the Catalonia (Spain), the former Direcció General de Recerca i Innovació en Salut (DGRIS) andInstitut Català de la Salut (ICS) that made this project possible, and all the health care professionals acting as a COVID-19 pandemic health taskforce in Catalonia. Also, we would like to specially thank the effort and dedication all the sentinel schools’ staff, students and families who participated in the project.