Will Summer Help Control COVID-19 Pandemic?

MedicalResearch.com Interview with:

Peter Jüni, MD, FESC
Director, Applied Health Research Centre
Li Ka Shing Knowledge Institute of St Michael’s Hospital
Department of Medicine
University of Toronto, Ontario 

MedicalResearch.com: What is the background for this study?

Response: It is unclear whether seasonal changes, school closures or other public health interventions will result in a slowdown of the current coronavirus disease 2019 (COVID-19) pandemic. We studied 144 geopolitical areas around the world with more than 375,000 COVID-19 cases by March 27 to determine whether epidemic growth is globally associated with climate or public health interventions intended to reduce transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

MedicalResearch.com: What are the main findings?

Response: We found no evidence that countries experiencing warm weather in March had any advantage over colder climates. Conversely, public health interventions, specifically restrictions of mass gatherings, school closures and social distancing measures, proved highly effective to slow down the epidemic growth of COVID-19. We found some evidence that high absolute or relative humidity might somewhat decrease transmission – possibly because aerosol droplets fall to the ground more quickly or virus particles become unstable in wet, heavy air. But this weak observed association paled in comparison to the impact of public health interventions.

MedicalResearch.com: What should readers take away from your report?

Response: Summer won’t help us to control the COVID-19 pandemic. Conversely, restrictions of mass gatherings, school closures and social distancing actually work. This means that we all need to get ready now for a marathon and responsibly contribute day by day to controlling the pandemic, following the principles of social distancing for at least another year. When lifting restrictions, we need to be smart and creative in finding ways of getting back to a ‘new normal’ without risking another surge.

MedicalResearch.com: What recommendations do you have for future research as a result of this work?

Response: This study was meant as a prospectively designed early response to the COVID-19 pandemic, providing first evidence to inform decision making. Future studies, based on more data, will hopefully be able to reliably estimate the independent contributions of different public health interventions and will shed light on the effect of timing of implementing and lifting interventions. Different strategies to reopen schools and lift other restrictions should ideally be rigorously tested in randomized trials.

MedicalResearch.com: Is there anything else you would like to add?

Response: If schools are re-opened, class sizes should stay below 12 to 15 students and mass gatherings on school yards would need to be strictly avoided, also in the morning when entering schools.

Peter Jüni is a Tier 1 Canada Research Chair in Clinical Epidemiology of Chronic Diseases. Pavlos Bobos is a recipient of a Frederick Banting and Charles Best Canada Graduate Scholarships of the Canadian Institutes of Health Research. Arthur S. Slutsky is supported by grants # FDN143285 and 137772 from the Canadian Institutes of Health Research. This research was completed, in part, with funding from the Canada Research Chairs Program and the Canadian Institutes of Health Research.


Peter JüniMartina RothenbühlerPavlos BobosKevin E. ThorpeBruno R. da CostaDavid N. FismanArthur S. SlutskyDionne Gesink



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Last Updated on May 12, 2020 by Marie Benz MD FAAD