Remember to sleep amid pandemics!

Is the previously described risk reduction of long-lasting COVID symptoms due to mRNA vaccinations against SARS-CoV-2 less pronounced among people who either sleep too little or too long?
Remember to sleep amid pandemics!

ICOSS is an international research collaboration project that started in 2020. It involves multiple leading researchers in the field of Sleep Science from several countries across four continents: Europe, North America, South America, and Asia. The project's aims have been to study how the COVID-19 pandemic and SARS-CoV-2 infections have impacted sleep, circadian rhythms, fatigue, daytime functioning, and health in general adult populations. In the first ICOSS survey, conducted during May and August 2020, the impact of the COVID-19 pandemic on sleep and circadian rhythms in adults from all over the world was investigated. For example, the project found that insomnia, anxiety, depression, and nightmares were more prevalent during the COVID-19 pandemic than before it.1,2 In 2021, the second ICOSS survey was conducted to disentangle the complex interplay between sleep disruption and sleep disorders on the one hand, and long-lasting COVID-19 symptoms on the other hand. It has previously been described that long-lasting COVID symptoms are lower after receiving COVID-19 mRNA vaccines.3 In an article now published in Translational Psychiatry,4 the ICOSS researchers investigated whether the association between lower odds of long-lasting CVOID symptoms and mRNA vaccination is less pronounced among people who either sleep too little (<six hours per night) or too long (> nine hours per night). While receipt of at least two mRNA vaccinations was associated with lowers odds of reporting long-lasting COVID symptoms (e.g., breathing issues or feeling feverish), they also observed that this risk reduction was less pronounced among short sleepers. In this context, it has previously been shown that short nighttime sleep can compromise the ability of the human body to cope with viral infections.5 For example, restricting sleep to 4 h per night resulted in half the IgG antibody titers obtained after vaccination against the seasonal influenza virus compared with their non-restricted controls.6

In addition to short nighttime sleep, the ICOSS collaborators also reported that long nighttime sleep duration might concur with an increased risk of long-lasting COVID symptoms, despite being double-vaccinated. However, considering only participants who had slept as much before the pandemic as they did during the pandemic, the association between long sleep and long-lasting COVID symptoms was no longer significant.4

Despite obvious limitations, such as that the analysis was based on survey data and possible infections with SARS-CoV-2 were not confirmed by laboratory tests,4 these findings indicate that too short nighttime sleep may limit the protective potential of virus vaccination. Hence, promoting healthy sleep in our sleepless societies may be helpful for future viral pandemics.7    

Acknowledgements: The poster image was created with


  1. Morin CM, Bjorvatn B, Chung F, Holzinger B, Partinen M, Penzel T, et al. Insomnia, anxiety, and depression during the COVID-19 pandemic: an international collaborative study. Sleep Med 87, 38-45 (2021).
  2. Scarpelli S, Nadorff MR, Bjorvatn B, Chung F, Dauvilliers Y, Espie C, et al. Nightmares in People with COVID-19: Did Coronavirus Infect Our Dreams? Nat Sci Sleep 14, 93-108 (2022). 
  3. Ayoubkhani D, Bermingham C, Pouwels KB, Glickman M, Nafilyan V, Zaccardi F, et al. Trajectory of long covid symptoms after covid-19 vaccination: community based cohort study. BMJ 377, e069676 (2022).
  4. Xue P, Merikanto I, Chung F, Morin CM, Espie C, Bjorvatn B,  al. Persistent short nighttime sleep duration is associated with a greater post-COVID risk in fully mRNA-vaccinated individuals. Translational Psychiatry (2023)13:32.
  5. Besedovsky L, Lange T, Haack M. The Sleep-Immune Crosstalk in Health and Disease. Physiol Rev 99, 1325-1380 (2019). 
  6. Spiegel K, Sheridan JF, Van Cauter E.Effect of sleep deprivation on response to immunization. JAMA 288, 1471-1472 (2002). 
  7. Benedict C, Cedernaes J. Could a good night's sleep improve COVID-19 vaccine efficacy? Lancet Respir Med 9, 447-448 (2021). 

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