Effects of hydrometeorological and other factors on SARS-CoV-2 reproduction number in three contiguous countries of tropical Andean South America: a spatiotemporally disaggregated time series analysis

Josh M Colston; Patrick Hinson; Nhat-Lan H Nguyen; Yen Ting Chen; Hamada S Badr; Gaige H Kerr; Lauren M Gardner; David N Martin; Antonio M Quispe; Francesca Schiaffino; Margaret N Kosek; Benjamin F Zaitchik

doi:10.1016/j.ijregi.2022.11.007

Effects of hydrometeorological and other factors on SARS-CoV-2 reproduction number in three contiguous countries of tropical Andean South America: a spatiotemporally disaggregated time series analysis

IJID Reg. 2023 Mar:6:29-41. doi: 10.1016/j.ijregi.2022.11.007. Epub 2022 Nov 20.

Authors

Affiliations

¹ Division of Infectious Diseases and International Health, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA.
² College of Arts and Sciences, University of Virginia, VA, USA.
³ Department of Emergency Medicine, Chi-Mei Medical Center, Tainan, Taiwan.
⁴ Department of Earth and Planetary Sciences, Johns Hopkins Krieger School of Arts and Sciences, Baltimore, MD, 21218, USA.
⁵ Department of Environmental and Occupational Health, Milken Institute School of Public Health, George Washington University, Washington, DC, USA.
⁶ Department of Civil and Systems Engineering, Johns Hopkins University, Baltimore, MD, USA.
⁷ Claude Moore Health Sciences Library, University of Virginia School of Medicine, VA, USA.
⁸ Postgraduate School, Universidad Continental, Lima, Peru.
⁹ Faculty of Veterinary Medicine, Universidad Peruana Cayetano Heredia, Lima, Peru.
¹⁰ Division of Infectious Diseases and International Health and Public Health Sciences, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA.

Abstract

Background: The COVID-19 pandemic has caused societal disruption globally, and South America has been hit harder than other lower-income regions. This study modeled the effects of six weather variables on district-level SARS-CoV-2 reproduction numbers (R_t ) in three contiguous countries of tropical Andean South America (Colombia, Ecuador, and Peru), adjusting for environmental, policy, healthcare infrastructural and other factors.

Methods: Daily time-series data on SARS-CoV-2 infections were sourced from the health authorities of the three countries at the smallest available administrative level. R_t values were calculated and merged by date and unit ID with variables from a unified COVID-19 dataset and other publicly available sources for May-December, 2020. Generalized additive models were fitted.

Findings: Relative humidity and solar radiation were inversely associated with SARS-CoV-2 R_t . Days with radiation above 1000 kJ/m² saw a 1.3% reduction in R_t , and those with humidity above 50% recorded a 0.9% reduction in R_t . Transmission was highest in densely populated districts, and lowest in districts with poor healthcare access and on days with lowest population mobility. Wind speed, temperature, region, aggregate government policy response, and population age structure had little impact. The fully adjusted model explained 4.3% of R_t variance.

Interpretation: Dry atmospheric conditions of low humidity increase district-level SARS-CoV-2 reproduction numbers, while higher levels of solar radiation decrease district-level SARS-CoV-2 reproduction numbers - effects that are comparable in magnitude to population factors like lockdown compliance. Weather monitoring could be incorporated into disease surveillance and early warning systems in conjunction with more established risk indicators and surveillance measures.

Funding: NASA's Group on Earth Observations Work Programme (16-GEO16-0047).

Keywords: COVID-19; Colombia; Ecuador; Latin America; Peru; SARS-CoV-2; climate; coronavirus; hydrometeorology; pandemic disease.

Grants and funding

U01GH002270/ACL/ACL HHS/United States