Weather Conditions and COVID-19 Incidence in a Cold Climate: A Time-Series Study in Finland.

Behzad Heibati,Francesca Dominici,Wenge Wang,Zhijie Zhang,Niilo R I Ryti,Jouni J K Jaakkola,Alan Ducatman

doi:10.3389/fpubh.2020.605128

Abstract

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.

Highlights

The current coronavirus disease 2019 (COVID-19) is spreading globally at an accelerated rate
Dewpoint was excluded from the correlation coefficient matrix (Figure 1B) and temperature range, wind speed and pressure were excluded from the univariate generalized additional model (GAM) model
On the basis of previous knowledge about weather and COVID19 incidence [1,2,3,4] and several other viral diseases, including SARS-CoV [5], h. influenza [6], and rhino viruses [7], we tested the hypothesis that low temperature and low relative humidity increase the incidence of COVID-19

Summary

Introduction

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. In a study of 17 Chinese cities, COVID-19 incidence was inversely related to an increase in temperature and diurnal temperature range [4]. Two studies conducted in subtropical cities of Brazil both provided evidence that an increase in temperature is related to a decrease in COVID-19 incidence [1, 3]. This is consistent with previous evidence on the associations between weather and temperature per se for several other viral diseases, including SARS-CoV [5], h. The independent effect of environmental factors on the incidence of COVID-19 in Finland has not been studied

Methods

Results

Discussion

Conclusion