Skip to main content

Main menu

  • Home
  • Current issue
  • ERJ Early View
  • Past issues
  • For authors
    • Instructions for authors
    • Submit a manuscript
    • Author FAQs
    • Open access
    • COVID-19 submission information
  • Alerts
  • Podcasts
  • Subscriptions
  • ERS Publications
    • European Respiratory Journal
    • ERJ Open Research
    • European Respiratory Review
    • Breathe
    • ERS Books
    • ERS publications home

User menu

  • Log in
  • Subscribe
  • Contact Us
  • My Cart

Search

  • Advanced search
  • ERS Publications
    • European Respiratory Journal
    • ERJ Open Research
    • European Respiratory Review
    • Breathe
    • ERS Books
    • ERS publications home

Login

European Respiratory Society

Advanced Search

  • Home
  • Current issue
  • ERJ Early View
  • Past issues
  • For authors
    • Instructions for authors
    • Submit a manuscript
    • Author FAQs
    • Open access
    • COVID-19 submission information
  • Alerts
  • Podcasts
  • Subscriptions

No Association of COVID-19 transmission with temperature or UV radiation in Chinese cities

Ye Yao, Jinhua Pan, Zhixi Liu, Xia Meng, Weidong Wang, Haidong Kan, Weibing Wang
European Respiratory Journal 2020; DOI: 10.1183/13993003.00517-2020
Ye Yao
1Fudan University, Shanghai, China
2contributed equally to this letter
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Jinhua Pan
1Fudan University, Shanghai, China
2contributed equally to this letter
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for Jinhua Pan
Zhixi Liu
1Fudan University, Shanghai, China
2contributed equally to this letter
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Xia Meng
1Fudan University, Shanghai, China
2contributed equally to this letter
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Weidong Wang
1Fudan University, Shanghai, China
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Haidong Kan
1Fudan University, Shanghai, China
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Weibing Wang
1Fudan University, Shanghai, China
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • Article
  • Figures & Data
  • Info & Metrics
  • PDF
Loading

Abstract

No Association of COVID-19 transmission with temperature or UV radiation in Chinese cities

Backgrounds

The Coronavirus (COVID-19) epidemic, which was first reported in December 2019 in Wuhan, China, has caused 80 904 confirmed cases as of 9 March 2020, with 28 673 cases being reported outside of China. It has been declared a pandemic by the World Health Organization which exhibited human-to-human transmissibility and spread rapidly across countries [1]. Although Chinese government has taken various measures to control city-to-city transmission (e.g. shutting down cities, extending holidays) and many countries have implemented measures such as airport screening and testing of patients who have reported symptoms, the number of cases still increases quickly throughout the world.

Previous studies have shown the importance of weather variables in the transmission of infectious diseases, including, but not limited to, influenza and severe acute respiratory syndrome (SARS). For example, a sharp change of ambient temperature was associated with increased risk of SARS [2, 3]. Also, influenza transmission is often enhanced in the presence of cold and/or dry air [4]. In northern Europe, low temperature and low UV Indexes were correlated with peaks of influenza virus activity during 2010–2018 [5]. Therefore, it is hypothesised that COVID-19 transmission may decrease or even disappear when the temperature and UV radiation increase in the summer. In this study, we aim to determine the association of meteorological factors with transmission of COVID-19 in various Chinese cities.

Methods

We collected COVID-19 confirmed case information in China reported by the National Health Commission (www.nhc.gov.cn/xcs/xxgzbd/gzbd_index.shtml) and the Provincial Health Commissions of China (http://wjw.hubei.gov.cn/bmdt/ztzl/fkxxgzbdgrfyyq/). We used the cumulative number of confirmed cases from 224 cities (207 outside Hubei, 17 inside Hubei) with no less than 10 cases as of Mar 9, and calculated basic reproduction number (R0) for 62 cities (50 outside Hubei, 12 inside Hubei) with more than 50 cases as of February 10 (COVID-19 peak time in China). R0 means the expected number of secondary cases generated by an initial infectious individual, in a completely susceptible population. If R0<1, then the disease free equilibrium is locally asymptotically stable; whereas if R0>1, then it is unstable. Thus, R0 is a threshold parameter.

Meteorological data, including daily mean temperature and relative humidity, were collected from the China Meteorological Data Sharing Service System. Regarding the UV radiation, daily erythemally weighted daily dose (EDD) data were extracted from the Dutch-Finnish Ozone Monitoring Instrument (OMI) Level 2 UV irradiance products with version 003 (OMUVB V003) at 13 km×24 km resolution. OMI is a nadir-viewing spectrometer aboard the NASA Aura satellite covering UV wavelength from 270 nm to 380 nm. Average of EDD values from OMI pixels matched within the city area was assigned as the daily mean EDD level for the corresponding city.

We used R to assess the associations of meteorological factors (including temperature, relative humidity and UV radiation) with the spread ability of COVID-19. In particular, we averaged daily temperature, maximum temperature, minimum temperature, relative humanity and UV radiation (EDD data) from early January to early March for 224 cities. Multiple regression methods were used to explore the association of meteorological factors with cumulative incidence rate and R0 in the same period.

Results

Among the 224 cities, the mean±standard deviation and range were (5.9±7.5, −17.8–22.0°C) for temperature and (1332.5±594.0, 385.3222.0 J·m−2) for EDD. Temperature and EDD tended to decrease toward high latitude and altitude. The mean±standard deviation and range were (60.3±324.0, 1.9–4509.1/106) for cumulative incidence rate in 224 cities and (1.4±0.3, 0.6–2.5) for R0 in 62 cities. The top 3 cities with the highest R0 and top 15 cities with highest cumulative incidence rate were all in Hubei Province.

After adjustment for relative humidity and UV, as shown in figure 1 left panel, temperature held no significant associations with cumulative incidence rate (χ2=5.03, p=0.28) or R0 (χ2=0.93, p=0.92), in cities both outside (green points) and inside Hubei (blue points), which indicated that the spread ability of COVID-19 would not change with increasing temperature. Similarly, as shown in figure 1 right panel, UV was not significantly associated with cumulative incidence rate (χ2=5.50, p=0.24) and R0 (χ2=0.91, p=0.92) after adjustment for temperature and relative humidity, suggesting that the spread ability of COVID-19 would not change with increasing UV exposure. In addition, we did not find significant associations of relative humanity, maximum temperature and minimum temperature with cumulative incidence rate or R0 of COVID-19.

FIGURE 1
  • Download figure
  • Open in new tab
  • Download powerpoint
FIGURE 1

Temperature, Ultraviolet and Spread Ability of COVID-19“Left Panel: Cumulative incidence rate and Basic Reproduction Number (R0) hold no significant associations (χ2=5.03, p=0.28 & χ2=0.93, p=0.92) with temperature in cities outside (blue points) and inside Hubei (green points). Relative humidity and ultraviolet effects have been adjusted in the model.” Right Panel: Cumulative incidence rate and R0 hold no significant associations χ2=5.50, p=0.24 & χ2=0.91, p=0.92) with ultraviolet in cities outside and inside Hubei. Temperature and relative humidity effects have been adjusted in the model.

Discussions

Previous results on the relationship between respiratory-borne infectious diseases and temperature indicated that both SARS and influenza need to survive under certain temperature conditions, and increasing temperature can reduce the ability of SARS virus and influenza virus to spread [6, 7]. The underlying hypothesis for why warmer seasons tends to decrease the spread of viruses includes higher vitamin D levels, resulting in better immune responses [8]; increased UV radiation; and no school in the summer (when children are clustered together, transmission rates of flu and measles increase). Reports of UV and respiratory diseases have also been studied, and previous studies have shown that high levels of UV exposure can reduce the spread of SARS-COV virus [9].

The results from this study, however, do not follow this expected pattern. According to the current results, cumulative incidence rate and R0 of COVID-19 held no significant associations with ambient temperature, suggesting that ambient temperature has no significant impact on the transmission ability of SARS-CoV-2. This is quite similar with MERS epidemic in the Arabian Peninsula where MERS cases continue when temperatures are 45°C [10]. Other newly emergent zoonotic disease, such as Ebola or pandemic strains of influenza, have also occurred in unpredictable patterns. Even though the transmission of SARS, which began in November, 2002, and ended in July, 2003, suggests it might be seasonal, but it also might have been controlled by effective case finding, contact tracing and quarantine.

Our study has limitations. First, our study period may not represent a whole meteorological pattern associated with transmissibility of COVID-19. However, we did not observe reduced transmissibility of COVID-19 in some southern Chinese cities (e.g. Sanya, Haikou, and Danzhou) with average daily temperature already over 20℃ (maximal temperature >30℃), suggesting the robustness of our findings. Certainly, further studies with longer follow-up period and wider temperature range are warranted. Second, given the ecological nature of study, other city-level factors, such as implementation ability of COVID-19 control policy, urbanisation rate, and availability of medical resources, may affect the transmissibility of COVID-19 and confound our findings. Future studies should develop complicated models with high spatial-temporal resolution to assess the relationship between meteorological conditions and epidemiologic characteristics of COVID-19.

In summary, our study does not support the hypothesis that high temperature and UV radiation can reduce the transmission of COVID-19. It might be premature to count on warmer weather to control COVID-19.

Footnotes

  • Author contributions: Ye Yao, Weibing Wang, and Haidong Kan designed the study. Jinhua Pan, Zhixi Liu, Ye Yao, and Weibing Wang collected COVID-19 incidence data and gained insight into the biology and natural history of the virus. Jinhua Pan, Zhixi Liu., Ye Yao and Weibing Wang developed the model and obtained the related parameters. Weidong Wang and Haidong Kan collected meteorological factors. Ye Yao, Jinhua Pan, Zhixi Liu, and Xia Meng drafted the manuscript. Haidong Kan and Weibing Wang revised the manuscript. All authors critically reviewed and approved the final version of the manuscript.

  • Support statement: This study was sponsored by the Bill & Melinda Gates Foundation (Grant No. OPP1216424) and Fudan University Research Project on COVID-19 Emergency (Grant No. IDF201007). Bill and Melinda Gates Foundation; DOI: http://dx.doi.org/10.13039/100000865; Grant: Grant No. OPP1216424; Fudan University; DOI: http://dx.doi.org/10.13039/501100003347; Grant: Grant No. IDF201007.

  • Conflict of interest: Dr. Yao has nothing to disclose.

  • Conflict of interest: Miss. Pan has nothing to disclose.

  • Conflict of interest: Miss. Liu has nothing to disclose.

  • Conflict of interest: Dr. Meng has nothing to disclose.

  • Conflict of interest: Mr. Wang has nothing to disclose.

  • Conflict of interest: Dr. Kan has nothing to disclose.

  • Conflict of interest: Dr. Wang has nothing to disclose.

  • Received March 1, 2020.
  • Accepted March 29, 2020.
  • Copyright ©ERS 2020
http://creativecommons.org/licenses/by-nc/4.0/

This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial Licence 4.0.

References

  1. ↵
    1. Li Q,
    2. Guan X,
    3. Wu P, et al.
    Early Transmission Dynamics in Wuhan, China, of Novel Coronavirus-Infected Pneumonia. N Engl J Med 2020; 382: 1199–1207. doi:10.1056/NEJMoa2001316
    OpenUrlCrossRefPubMed
  2. ↵
    1. Tan J,
    2. Mu L,
    3. Huang J, et al.
    An initial investigation of the association between the SARS outbreak and weather: with the view of the environmental temperature and its variation. J Epidemiol Community Health 2005; 59: 186–192. doi:10.1136/jech.2004.020180
    OpenUrlAbstract/FREE Full Text
  3. ↵
    (WHO), W. H. O. Coronavirus disease (COVID-2019) situation reports. www.who.int/docs/default-source/coronaviruse/situation-reports/20200227-sitrep-38-covid-19.pdf?sfvrsn=9f98940c_2.
  4. ↵
    1. Xu Z,
    2. Hu W,
    3. Williams G, et al.
    Air pollution, temperature and pediatric influenza in Brisbane, Australia. Environ Int 2013; 59: 384–388. doi:10.1016/j.envint.2013.06.022
    OpenUrlCrossRefPubMedWeb of Science
  5. ↵
    1. Ianevski A,
    2. Zusinaite E,
    3. Shtaida N, et al.
    Low Temperature and Low UV Indexes Correlated with Peaks of Influenza Virus Activity in Northern Europe during 2010–2018. Viruses 2019; 11: E207. doi:10.3390/v11030207
    OpenUrl
  6. ↵
    1. Jaakkola K,
    2. Saukkoriipi A,
    3. Jokelainen J, et al.
    Decline in temperature and humidity increases the occurrence of influenza in cold climate. Environ Health 2014; 13: 22. doi:10.1186/1476-069X-13-22
    OpenUrl
  7. ↵
    1. Chan KH,
    2. Peiris JS,
    3. Lam SY, et al.
    The Effects of Temperature and Relative Humidity on the Viability of the SARS Coronavirus. Adv Virol 2011; 2011: 734690.
    OpenUrlCrossRefPubMed
  8. ↵
    1. Aranow C
    . Vitamin D and the immune system. J Investig Med 2011; 59: 881–886. doi:10.2310/JIM.0b013e31821b8755
    OpenUrlAbstract/FREE Full Text
  9. ↵
    1. Duan SM,
    2. Zhao XS,
    3. Wen RF, et al.
    Stability of SARS coronavirus in human specimens and environment and its sensitivity to heating and UV irradiation. Biomed Environ Sci 2003; 16: 246–255.
    OpenUrlPubMedWeb of Science
  10. ↵
    1. Alshukairi AN,
    2. Zheng J,
    3. Zhao J, et al.
    High Prevalence of MERS-CoV Infection in Camel Workers in Saudi Arabia. mBio 2018; 9: e01985-18. doi:10.1128/mBio.01985-18
    OpenUrlAbstract/FREE Full Text
View Abstract
PreviousNext
Back to top
View this article with LENS
Vol 57 Issue 1 Table of Contents
European Respiratory Journal: 57 (1)
  • Table of Contents
  • Index by author
Email

Thank you for your interest in spreading the word on European Respiratory Society .

NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.

Enter multiple addresses on separate lines or separate them with commas.
No Association of COVID-19 transmission with temperature or UV radiation in Chinese cities
(Your Name) has sent you a message from European Respiratory Society
(Your Name) thought you would like to see the European Respiratory Society web site.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Print
Alerts
Sign In to Email Alerts with your Email Address
Citation Tools
No Association of COVID-19 transmission with temperature or UV radiation in Chinese cities
Ye Yao, Jinhua Pan, Zhixi Liu, Xia Meng, Weidong Wang, Haidong Kan, Weibing Wang
European Respiratory Journal Jan 2020, 2000517; DOI: 10.1183/13993003.00517-2020

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero

Share
No Association of COVID-19 transmission with temperature or UV radiation in Chinese cities
Ye Yao, Jinhua Pan, Zhixi Liu, Xia Meng, Weidong Wang, Haidong Kan, Weibing Wang
European Respiratory Journal Jan 2020, 2000517; DOI: 10.1183/13993003.00517-2020
del.icio.us logo Digg logo Reddit logo Technorati logo Twitter logo CiteULike logo Connotea logo Facebook logo Google logo Mendeley logo
Full Text (PDF)

Jump To

  • Article
    • Abstract
    • Backgrounds
    • Methods
    • Results
    • Discussions
    • Footnotes
    • References
  • Figures & Data
  • Info & Metrics
  • PDF
  • Tweet Widget
  • Facebook Like
  • Google Plus One

More in this TOC Section

  • Plasma ACE2 activity is persistently elevated following SARS-CoV-2 infection: implications for COVID-19 pathogenesis and consequences
  • Residual symptoms and lower lung function in patients recovering from SARS-CoV-2 infection
  • Residential air pollution increases the risk for persistent pulmonary hypertension after pulmonary endarterectomy
Show more Research letter

Related Articles

Navigate

  • Home
  • Current issue
  • Archive

About the ERJ

  • Journal information
  • Editorial board
  • Reviewers
  • CME
  • Press
  • Permissions and reprints
  • Advertising

The European Respiratory Society

  • Society home
  • myERS
  • Privacy policy
  • Accessibility

ERS publications

  • European Respiratory Journal
  • ERJ Open Research
  • European Respiratory Review
  • Breathe
  • ERS books online
  • ERS Bookshop

Help

  • Feedback

For authors

  • Instructions for authors
  • Submit a manuscript
  • ERS author centre

For readers

  • Alerts
  • Subjects
  • Podcasts
  • RSS

Subscriptions

  • Accessing the ERS publications

Contact us

European Respiratory Society
442 Glossop Road
Sheffield S10 2PX
United Kingdom
Tel: +44 114 2672860
Email: journals@ersnet.org

ISSN

Print ISSN:  0903-1936
Online ISSN: 1399-3003

Copyright © 2021 by the European Respiratory Society