Impact of Temperature and Relative Humidity on the Transmission of COVID-19: A Modeling Study in China and the United States
Posted: 10 Mar 2020 Last revised: 24 Jan 2021
Date Written: March 9, 2020
We aim to assess the impact of temperature and relative humidity on the transmission of COVID-19 across communities after accounting for community-level factors such as demographics, socioeconomic status, and human mobility status. A retrospective cross-sectional regression analysis via the Fama-MacBeth procedure is adopted. We use the data for COVID-19 daily symptom-onset cases for 100 Chinese cities and COVID-19 daily confirmed cases for 1,005 U.S. counties. A total of 69,498 cases in China and 740,843 cases in the U.S. are used for calculating the effective reproductive numbers. Regression analysis of the impact of temperature and relative humidity on the effective reproductive number (R value). Statistically significant negative correlations are found between temperature/relative humidity and the effective reproductive number (R value) in both China and the U.S. Higher temperature and higher relative humidity potentially suppress the transmission of COVID-19. Specifically, an increase in temperature by 1 degree Celsius is associated with a reduction in the R value of COVID-19 by 0.026 (95% CI [-0.0395,-0.0125]) in China and by 0.020 (95% CI [-0.0311, -0.0096]) in the U.S.; an increase in relative humidity by 1% is associated with a reduction in the R value by 0.0076 (95% CI [-0.0108,-0.0045]) in China and by 0.0080 (95% CI [-0.0150,-0.0010]) in the U.S. Therefore, the potential impact of temperature/relative humidity on the effective reproductive number alone is not strong enough to stop the pandemic. This paper was previously circulated under the title “High Temperature and High Humidity Reduce the Transmission of COVID-19”.
Note: Funding: This work was supported by the National Key R&D Program of China (2019YFB2102100 to Jingyuan Wang) and the National Natural Science Foundation of China (Grant No. 61572059 and 71531001 to Jingyuan Wang and U1811463 to Weifeng Lv).
Declaration of Interest: There is no competing interest declaration for all authors.
Keywords: COVID-19, Transmission, Effective Reproductive Number, Temperature, Humidity
JEL Classification: I1
Suggested Citation: Suggested Citation