University of Oulu

Heibati B, Wang W, Ryti NRI, Dominici F, Ducatman A, Zhang Z and Jaakkola JJK (2021) Weather Conditions and COVID-19 Incidence in a Cold Climate: A Time-Series Study in Finland. Front. Public Health 8:605128. doi: 10.3389/fpubh.2020.605128

Weather conditions and COVID-19 incidence in a cold climate : a time-series study in Finland

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Author: Heibati, Behzad1,2,3; Wang, Wenge4; Ryti, Niilo R. I.1,2,3;
Organizations: 1Faculty of Medicine, Center for Environmental and Respiratory Health Research, University of Oulu, Oulu, Finland
2Faculty of Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
3Medical Research Center Oulu, Oulu University Hospital, University of Oulu, Oulu, Finland
4Department of Epidemiology and Health Statistics, School of Public Health, Fudan University, Shanghai, China
5Department of Biostatistics, T. H. Chan School of Public Health, Harvard University, Boston, MA, United States
6West Virginia University School of Public Health, Morgantown, WV, United States
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.6 MB)
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Language: English
Published: Frontiers Media, 2021
Publish Date: 2021-05-20


Background: The current coronavirus disease 2019 (COVID-19) is spreading globally at an accelerated rate. There is some previous evidence that weather may influence the incidence of COVID-19 infection. We assessed the role of meteorological factors including temperature (T) and relative humidity (RH) considering the concentrations of two air pollutants, inhalable coarse particles (PM₁₀) and nitrogen dioxide (NO₂) in the incidence of COVID-19 infections in Finland, located in arctic-subarctic climatic zone.

Methods: We retrieved daily counts of COVID-19 in Finland from Jan 1 to May 31, 2020, nationwide and separately for all 21 hospital districts across the country. The meteorological and air quality data were from the monitoring stations nearest to the central district hospital. A quasi-Poisson generalized additional model (GAM) was fitted to estimate the associations between district-specific meteorological factors and the daily counts of COVID-19 during the study period. Sensitivity analyses were conducted to test the robustness of the results.

Results: The incidence rate of COVID-19 gradually increased until a peak around April 6 and then decreased. There were no associations between daily temperature and incidence rate of COVID-19. Daily average RH was negatively associated with daily incidence rate of COVID-19 in two hospital districts located inland. No such association was found nationwide.

Conclusions: Weather conditions, such as air temperature and relative humidity, were not related to the COVID-19 incidence during the first wave in the arctic and subarctic winter and spring. The inference is based on a relatively small number of cases and a restricted time period.

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Series: Frontiers in public health
ISSN: 2296-2565
ISSN-E: 2296-2565
ISSN-L: 2296-2565
Volume: 8
Article number: 605128
DOI: 10.3389/fpubh.2020.605128
Type of Publication: A1 Journal article – refereed
Field of Science: 3142 Public health care science, environmental and occupational health
Funding: BH was funded by the Biocenter Oulu. JJ was supported by the Academy of Finland (grant no. 310372). ZZ was supported by the National Major Infectious Disease Project of the Ministry of Science and Technology of China (grant no. 2017ZX10305501002), Key projects of the PLA logistics Scientific research Program (grant no. BHJ17J013), and the National Natural Science Foundation of China (grant nos. 81673239, 81973102), and Support for FD was provided by the Star-Friedman Challenge at Harvard University.
Academy of Finland Grant Number: 310372
Detailed Information: 310372 (Academy of Finland Funding decision)
Copyright information: © 2021 Heibati, Wang, Ryti, Dominici, Ducatman, Zhang and Jaakkola. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.