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University of Bergen
Bergen Sleep and Chronobiology Network

International COVID-19 Sleep Study (ICOSS)

The COVID-19 pandemic has generated a great deal of stress and anxiety about the fear of being infected with the virus, concerns about friends and family, about losing jobs and financial problems, and worries regarding the uncertainty about the outcome of the pandemic. In addition to these major stressors, the social confinement, limited daylight exposure, and changes in daily routines and working schedules are likely to produce major changes in sleep and circadian rhythms during this pandemic. The objective of this research is to evaluate the impact of the COVID-19 pandemic on sleep and circadian (24-hour) rhythms in adults. Specific objectives are to document the prevalence/incidence of sleep disorders/symptoms during the COVID-19 pandemic and investigate their associations with social confinement, risk of exposure to COVID-19, loss of work routines and psychological conditions (anxiety, depression, posttraumatic stress). This initiative is an international collaboration involving sleep experts from 16 countries across four continents (Europe, Asia, North and South America) around the world. Bjorvatn is part of the core leader group of this project, headed by Professor Markku Partinen from Finland.

Main content

Publications so far:

  1. Partinen M, Bjorvatn B, Holzinger B, Chung F, Penzel T, Espie CA, Morin CM, ICOSS-collaboration group. Sleep and circadian problems during the coronavirus disease 2019 (COVID-19) pandemic: the International COVID-19 Sleep Study (ICOSS). Journal of Sleep Research 2021; 30: e13206. PMID: 33179820.
  2. Benedict C, Partinen M, Bjorvatn B, Cedernaes J. Sleep in female healthcare workers during COVID-19: a cross-sectional study in Sweden during the flattening of the first wave. Annals of the American Thoracic Society 2021; 18: 1418-1420. PMID: 33448898.
  3. Chung F, Waseem R, Pham C, Penzel T, Han F, Bjorvatn B, Morin CM, Holzinger B, Espie CA, Benedict C, Cedernaes J, Saaresranta T, Wing YK, Nardorff MR, Dauvilliers Y, De Gennaro L, Plazzi G, Merikanto I, Matsui K, Leger D, Sieminski M, Mota-Rolim S, Inoue Y, Partinen M, ICOSS group. The association between high-risk of sleep apnea, comorbidities, and risk of COVID-19: A population based international harmonized study. Sleep & Breathing 2021; 25: 849-860. PMID: 33907966.
  4. Benedict C, Brandão LEM, Merikanto I, Partinen M, Bjorvatn B, Cedernaes J. Meal and sleep timing before and during the COVID-19 pandemic: A cross-sectional anonymous survey study from Sweden. Clocks & Sleep 2021; 3: 251-258. PMID: 33921946.
  5. Fränkl EC, Scarpelli S, Nadorff MR, Bjorvatn B, Bolstad C, Chan NY, Chung F, Dauvilliers Y, Espie CA, Inoue Y, Leger D, Macedo T, Matsui K, Merikanto I, Morin CM, Mota-Rolim S, Partinen M, Penzel T, Plazzi G, Sieminski M, Wing YK, De Gennaro L, Holzinger B. How our dreams changed during the COVID-19 pandemic: effects and correlates of dream recall frequency – a multinational study on 19,355 adults. Nature and Science of Sleep 2021; 13: 1573-1591. PMID: 34588830
  6. Morin CM, Bjorvatn B, Chung F, Holzinger B, Partinen M, Penzel T, Ivers H, Wing YK, Chan NY, Merikanto I, Mota-Rolim S, Macedo T, De Gennaro L, Leger D, Dauvilliers Y, Plazzi G, Nadorff MR, Bolstad CJ, Sieminski M, Benedict C, Cedernaes J, Inoue Y, Han F, Espie CA. Insomnia, anxiety and depression during the COVID-19 pandemic: An international collaborative study. Sleep Medicine 2021; 87: 38-45. PMID: 34508986.
  7. Brandao LEM, Martikainen T, Merikanto I, Holzinger B, Morin CM, Espie CA, Bolstad CJ, Leger D, Chung F, Plazzi G, Dauvilliers Y, Matsui K, De Gennaro L, Sieminski M, Nadorff MR, Chan NY, Wing YK, Mota-Rolim SA, Inoue Y, Partinen M, Benedict C, Bjorvatn B, Cedernaes J. Social jetlag changes during the COVID-19 pandemic as a predictor of insomnia – a multi-national survey study. Nature and Science of Sleep 2021; 13: 1711-1722. PMID: 34675720
  8. Partinen M, Holzinger B, Morin CM, Espie CA, Chung F, Penzel T, Benedikt C, Bolstad CJ, Cedernaes J, Chan NY, Dauvilliers Y, De Gennaro L, Han F, Inoue Y, Matsui K, Leger D, Cunha AS, Merikanto I, Mota-Rolim S, Nadorff M, Plazzi G, Schneider J, Sieminski M, Wing YK, Bjorvatn B. Sleep and daytime problems during the COVID-19 pandemic and effects of coronavirus infection, confinement and financial suffering: a multinational survey using a harmonized questionnaire. BMJ Open 2021; 11: e050672.  PMID: 34903540.
  9. Merikanto I, Kortesoja L, Benedict C, Chung F, Cedernaes J, Espie CA, Morin CM, Dauvilliers Y, Partinen M, De Gennaro L, Wing YK, Chan NY, Inoue Y, Matsui K, Holzinger B, Plazzi G, Mota-Rolim SA, Leger D, Penzel T, Bjorvatn B. Evening-types show highest increase of sleep and mental health problems during the COVID-19 pandemic – multinational study on 19,267 adults. SLEEP 2022; 45(2): zsab216. PMID: 34432058.
  10. Scrapelli S, Nadorff MR, Bjorvatn B, Chung F, Dauvilliers Y, Espie CA, Inoue Y, Matsui K, Merikanto I, Morin CM, Penzel T, Sieminski M, Fang H, Macêdo T, Mota-Rolim S, Leger D, Plazzi G, Chan NY, Partinen M, Bolstad CJ, Holzinger B, de Gennaro L. Nightmares in people with COVID-19: did coronavirus infect our dreams? Nature and Science of Sleep 2022; 14: 93-108. PMID: 35115852
  11. Holzinger B, Nierwetberg F, Chung F, Bolstad CJ, Bjorvatn B, Chan NY, Dauvilliers Y, Espie CA, Han F, Inoue Y, Leger D, Macêdo T, Matsui K, Merikanto I, Morin CM, Mota-Rolim SA, Partinen M, Plazzi G, Penzel T, Sieminski M, Wing YK, Scrapelli S, Nadorff MR, De Gennaro L. Has the COVID-19 pandemic traumatized us collectively? The impact of the COVID-19 pandemic on mental health and sleep factors via traumatization: A multinational Survey. Nature and Science of Sleep 2022; 14: 1469-1483. PMID: 36052103
  12. Liu Y, Partinen E, Chan NY, Dauvilliers Y, Inoue Y, De Gennaro L, Plazzi G, Bolstad CJ, Nadorff MR, Merikanto I, Bjorvatn B, Han F, Cunha AS, Mota-Rolim S, Leger D, Matsui K, Benedict C, Espie CA, Chung F, Morin CM, Cedernaes J, Sieminski M, Penzel T, Holzinger B, Partinen M, Wing YK. Dream-enactment behaviors during the COVID-19 pandemic: An international COVID-19 Sleep Study. Journal of Sleep Research 2023; 32: e13613. PMID: 35474255
  13. Merikanto I, Dauvilliers Y, Chung F, Wing YK, De Gennaro L, Holzinger B, Bjorvatn B, Morin CM, Penzel T, Benedict C, Bjelajac A, Chan NY, Espie CA, Hrubos-Strøm H, Inoue Y, Korman M, Landtblom A-M, Leger D, Matsui K, Mota-Rolim S, Nadorff MR, Plazzi G, Reis C, Yordanova J, Partinen M. Sleep symptoms are essential features of long-COVID – Comparing healthy controls to COVID-19 cases of different severity in the International COVID Sleep study (ICOSS-II). Journal of Sleep Research 2023; 32: e13754. PMID: 36208038
  14. Scrapelli S, De Santis A, Alfonsi V, Gorgoni M, Morin CM, Espie CA, Merikanto I, Chung F, Penzel T, Bjorvatn B, Dauvilliers Y, Holzinger B, Wing YK, Partinen M, Plazzi G, De Gennaro L. The role of sleep and dreams in long-COVID. Journal of Sleep Research 2023; 32(3): e13789. doi.org/10.1111/jsr.13789. PMID: 36398720
  15. Bjorvatn B, Merikanto I, Reis C, Korman M, Koscec Bjelajac A, Holzinger B, De Gennaro L, Wing YK, Morin CM, Espie CA, Benedict C, Landtblom A-M, Matsui K, Hrubos-Strøm H, Mota-Rolim S, Nadorff MR, Plazzi G, Chan RNY, Partinen M, Dauvilliers Y, Chung F, Forthun I. Shift workers are at increased risk of severe COVID-19 compared with day workers: Results from the International COVID Sleep Study (ICOSS) of 7141 workers. Chronobiology International 2023; 40; 114-122. PMID: 36412198
  16. Xue P, Merikanto I, Chung F, Morin CM, Espie CA, Bjorvatn B, Cedernaes J, Landtblom A-M, Penzel T, De Gennaro L, Holzinger B, Matsui K, Hrubos-Strøm H, Korman M, Leger D, Mota-Rolim S, Bolstad CJ, Nadorff M, Plazzi G, Reis C, Chan RNY, Wing YK, Yordanova J, Koscec Bjelajac A, Inoue Y, Partinen P, Dauvilliers Y, Benedict C. Persistent short nighttime sleep duration is associated with a greater post-COVID risk in fully mRNA-vaccinated individuals. Translational Psychiatry 2023; 13: 32. PMID: 36726008
  17. Sarkanen T, Partinen M, Bjorvatn B, Merikanto I, Benedict C, Nadorff M, Bolstad CJ, Espie C, Matsui K, Chung F, Morin CM, Wing YK, Penzel T, Macêdo T, Mota-Rolim S, Holzinger B, Plazzi G, De Gennaro L, Landtblom A-M, Inoue Y, Sieminski M, Leger D, Dauvilliers Y. Association between hypersomnolence and the COVID-19 pandemic: The International COVID-19 Sleep Study (ICOSS). Sleep Medicine 2023; 107: 108-115. PMID: 37156053
  18. Berezin L, Waseem R, Merikanto I, Benedict C, Holzinger B, De Gennaro L, Wing YK, Bjorvatn B, Korman M, Morin CM, Espie CA, Landtblom A-M, Penzel T, Matsui K, Hrubos-Strøm H, Mota-Rolim S, Nadorff MR, Plazzi G, Reis C, Chan RNY, Cunha AS, Yordanova J, Koscec Bjelajac A, Inoue Y, Dauvilliers Y, Partinen M, Chung F. Habitual short sleepers with pre-existing medical conditions are at higher risk of Long COVID. Journal of Clinical Sleep Medicine in press. doi: 10.5664/jcsm.10818. PMID: 37858285
  19. Chen S-J, Morin CM, Ivers H, Wing YK, Partinen M, Merikanto I, Holzinger B, Espie C, De Gennaro L, Dauvilliers Y, Chung F, Yordanova J, Vidović D, Reis C, Plazzi G, Penzel T, Nadorff M, Matsui K, Mota-Rolim S, Leger D, Landtblom A-M, Korman M, Inoue Y, Hrubos-Strøm H, Chan NY, Koscec Bjelajac A, Benedict C, Bjorvatn B. The association of insomnia with long COVID: An international collaborative study (ICOSS-II). Sleep Medicine 2023; 112: 216-222. doi: 10.1016/j.sleep.2023.09.034. PMID: 37922783
  20. Matsui K, Chung F, Koscec Bjelajac A, Merikanto I, Korman M, Mota-Rolim S, Cunha AS, Bjorvatn B, Xue P, Benedict C, Morin CM, Espie CA, Landtblom A-M, Penzel T, De Gennaro L, Holzinger B, Hrubos-Strøm H, Leger D, Bolstad CJ, Nadorff MR, Plazzi G, Reis C, Chan NY, Wing YK, Yordanova J, Dauvilliers Y, Partinen M, Inoue Y. Associations between changes in habitual sleep duration and lower self-rated health among COVID-19 survivors: Findings from a survey across 16 countries/regions. BMC Public Health in press.

Project period

2019 -

Contact person

Bjørn Bjorvatn

27.11.2023