@article{
 title = {The impact of temperature and absolute humidity on the coronavirus disease 2019 (COVID-19) outbreak - evidence from China},
 type = {article},
 year = {2020},
 pages = {2020.03.22.20038919},
 websites = {https://www.medrxiv.org/content/10.1101/2020.03.22.20038919v1},
 id = {9f765003-e369-3869-86d2-28be9c39e727},
 created = {2020-08-24T12:02:10.165Z},
 file_attached = {false},
 profile_id = {317fdcd2-b041-3222-bca0-702f39879f87},
 group_id = {b3d61752-de2a-32fd-8576-9b4f9cb05f29},
 last_modified = {2020-08-24T12:02:10.165Z},
 read = {false},
 starred = {false},
 authored = {false},
 confirmed = {true},
 hidden = {false},
 citation_key = {Shi2020a},
 private_publication = {false},
 abstract = {OBJECTIVE To investigate the impact of temperature and absolute humidity on the coronavirus disease 2019 (COVID-19) outbreak. DESIGN Ecological study. SETTING 31 provincial-level regions in mainland China. MAIN OUTCOME MEASURES Data on COVID-19 incidence and climate between Jan 20 and Feb 29, 2020. RESULTS The number of new confirm COVID-19 cases in mainland China peaked on Feb 1, 2020. COVID-19 daily incidence were lowest at -10 ℃ and highest at 10 ℃,while the maximum incidence was observed at the absolute humidity of approximately 7 g/m3. COVID-19 incidence changed with temperature as daily incidence decreased when the temperature rose. No significant association between COVID-19 incidence and absolute humidity was observed in distributed lag nonlinear models. Additionally, A modified susceptible-exposed-infectious-recovered (M-SEIR) model confirmed that transmission rate decreased with the increase of temperature, leading to further decrease of infection rate and outbreak scale. CONCLUSION Temperature is an environmental driver of the COVID-19 outbreak in China. Lower and higher temperatures might be positive to decrease the COVID-19 incidence. M-SEIR models help to better evaluate environmental and social impacts on COVID-19.

### Competing Interest Statement

The authors have declared no competing interest.

### Funding Statement

The work was supported by the National Key Research and Development Program of China to Prof Shuhua Xi (2018YFC1801204). The funders had no role in design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, and approval of the manuscript; or the decision to submit the manuscript for publication.

### Author Declarations

All relevant ethical guidelines have been followed; any necessary IRB and/or ethics committee approvals have been obtained and details of the IRB/oversight body are included in the manuscript.

Yes

All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.

Yes

Data on climate conditions and population were retrieved from official reports previously released in mainland China. Therefore, the ethical review was not required.},
 bibtype = {article},
 author = {Shi, Peng and Dong, Yinqiao and Yan, Huanchang and Li, Xiaoyang and Zhao, Chenkai and Liu, Wei and He, Miao and Tang, Shixing and Xi, Shuhua},
 doi = {10.1101/2020.03.22.20038919},
 journal = {medRxiv},
 number = {77}
}

{"_id":"GsLpYoE55DDvPfFui","bibbaseid":"shi-dong-yan-li-zhao-liu-he-tang-etal-theimpactoftemperatureandabsolutehumidityonthecoronavirusdisease2019covid19outbreakevidencefromchina-2020","authorIDs":[],"author_short":["Shi, P.","Dong, Y.","Yan, H.","Li, X.","Zhao, C.","Liu, W.","He, M.","Tang, S.","Xi, S."],"bibdata":{"title":"The impact of temperature and absolute humidity on the coronavirus disease 2019 (COVID-19) outbreak - evidence from China","type":"article","year":"2020","pages":"2020.03.22.20038919","websites":"https://www.medrxiv.org/content/10.1101/2020.03.22.20038919v1","id":"9f765003-e369-3869-86d2-28be9c39e727","created":"2020-08-24T12:02:10.165Z","file_attached":false,"profile_id":"317fdcd2-b041-3222-bca0-702f39879f87","group_id":"b3d61752-de2a-32fd-8576-9b4f9cb05f29","last_modified":"2020-08-24T12:02:10.165Z","read":false,"starred":false,"authored":false,"confirmed":"true","hidden":false,"citation_key":"Shi2020a","private_publication":false,"abstract":"OBJECTIVE To investigate the impact of temperature and absolute humidity on the coronavirus disease 2019 (COVID-19) outbreak. DESIGN Ecological study. SETTING 31 provincial-level regions in mainland China. MAIN OUTCOME MEASURES Data on COVID-19 incidence and climate between Jan 20 and Feb 29, 2020. RESULTS The number of new confirm COVID-19 cases in mainland China peaked on Feb 1, 2020. COVID-19 daily incidence were lowest at -10 ℃ and highest at 10 ℃,while the maximum incidence was observed at the absolute humidity of approximately 7 g/m3. COVID-19 incidence changed with temperature as daily incidence decreased when the temperature rose. No significant association between COVID-19 incidence and absolute humidity was observed in distributed lag nonlinear models. Additionally, A modified susceptible-exposed-infectious-recovered (M-SEIR) model confirmed that transmission rate decreased with the increase of temperature, leading to further decrease of infection rate and outbreak scale. CONCLUSION Temperature is an environmental driver of the COVID-19 outbreak in China. Lower and higher temperatures might be positive to decrease the COVID-19 incidence. M-SEIR models help to better evaluate environmental and social impacts on COVID-19.\n\n### Competing Interest Statement\n\nThe authors have declared no competing interest.\n\n### Funding Statement\n\nThe work was supported by the National Key Research and Development Program of China to Prof Shuhua Xi (2018YFC1801204). The funders had no role in design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, and approval of the manuscript; or the decision to submit the manuscript for publication.\n\n### Author Declarations\n\nAll relevant ethical guidelines have been followed; any necessary IRB and/or ethics committee approvals have been obtained and details of the IRB/oversight body are included in the manuscript.\n\nYes\n\nAll necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.\n\nYes\n\nI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).\n\nYes\n\nI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.\n\nYes\n\nData on climate conditions and population were retrieved from official reports previously released in mainland China. Therefore, the ethical review was not required.","bibtype":"article","author":"Shi, Peng and Dong, Yinqiao and Yan, Huanchang and Li, Xiaoyang and Zhao, Chenkai and Liu, Wei and He, Miao and Tang, Shixing and Xi, Shuhua","doi":"10.1101/2020.03.22.20038919","journal":"medRxiv","number":"77","bibtex":"@article{\n title = {The impact of temperature and absolute humidity on the coronavirus disease 2019 (COVID-19) outbreak - evidence from China},\n type = {article},\n year = {2020},\n pages = {2020.03.22.20038919},\n websites = {https://www.medrxiv.org/content/10.1101/2020.03.22.20038919v1},\n id = {9f765003-e369-3869-86d2-28be9c39e727},\n created = {2020-08-24T12:02:10.165Z},\n file_attached = {false},\n profile_id = {317fdcd2-b041-3222-bca0-702f39879f87},\n group_id = {b3d61752-de2a-32fd-8576-9b4f9cb05f29},\n last_modified = {2020-08-24T12:02:10.165Z},\n read = {false},\n starred = {false},\n authored = {false},\n confirmed = {true},\n hidden = {false},\n citation_key = {Shi2020a},\n private_publication = {false},\n abstract = {OBJECTIVE To investigate the impact of temperature and absolute humidity on the coronavirus disease 2019 (COVID-19) outbreak. 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Lower and higher temperatures might be positive to decrease the COVID-19 incidence. M-SEIR models help to better evaluate environmental and social impacts on COVID-19.\n\n### Competing Interest Statement\n\nThe authors have declared no competing interest.\n\n### Funding Statement\n\nThe work was supported by the National Key Research and Development Program of China to Prof Shuhua Xi (2018YFC1801204). The funders had no role in design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, and approval of the manuscript; or the decision to submit the manuscript for publication.\n\n### Author Declarations\n\nAll relevant ethical guidelines have been followed; any necessary IRB and/or ethics committee approvals have been obtained and details of the IRB/oversight body are included in the manuscript.\n\nYes\n\nAll necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.\n\nYes\n\nI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).\n\nYes\n\nI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.\n\nYes\n\nData on climate conditions and population were retrieved from official reports previously released in mainland China. 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