ICOSS is an international research collaboration project started at 2020 and lead from University of Helsinki. It involves multiple leading researches in the field of Sleep Science from several countries across four continents: Europe, North America, South America and Asia. Aim of the project is to study how COVID-19 pandemic and infection has influenced on sleep, circadian rhythms, fatigue, daytime functioning and health in general adult populations. In total, 18 countries have participated in the ICOSS study. First survey data was collected in May-August 2020 across 14 countries. Second survey was collected across 16 countries in May-December 2021, please find details at Research page.