loading page

Evolving Drivers of Brazilian SARS-CoV-2 Transmission: A Spatiotemporally Disaggregated Time Series Analysis of Meteorology, Policy, and Human Mobility
  • +4
  • Gaige Hunter Kerr,
  • Hamada S. Badr,
  • Alisson Barbieri,
  • Josh M Colston,
  • Lauren M. Gardner,
  • Margaret N Kosek,
  • Benjamin F Zaitchik
Gaige Hunter Kerr
The George Washington University

Corresponding Author:[email protected]

Author Profile
Hamada S. Badr
Johns Hopkins University
Author Profile
Alisson Barbieri
Federal University of Minas Gerais
Author Profile
Josh M Colston
University of Virginia School of Medicine
Author Profile
Lauren M. Gardner
Johns Hopkins University
Author Profile
Margaret N Kosek
Division of Infectious Diseases and International Health and Public Health Sciences, University of Virginia School of Medicine
Author Profile
Benjamin F Zaitchik
John Hopkins University
Author Profile


Brazil has been severely affected by the COVID-19 pandemic. Temperature and humidity have been purported as drivers of SARS-CoV-2 transmission, but no consensus has been reached in the literature regarding the relative roles of meteorology, governmental policy, and mobility on transmission in Brazil. We compiled data on meteorology, governmental policy, and mobility in Brazil’s 26 states and one federal district from June 2020 to August 2021. Associations between these variables and the time-varying reproductive number (Rt) of SARS-CoV-2 were examined using generalized additive models fit to data from the entire fifteen-month period and several shorter, three-month periods. Accumulated local effects and variable importance metrics were calculated to analyze the relationship between input variables and Rt. We found that transmission is strongly influenced by unmeasured sources of between-state heterogeneity and the near-recent trajectory of the pandemic. Increased temperature generally was associated with decreased transmission and specific humidity with increased transmission. However, the impact of meteorology, policy, and mobility on Rt varied in direction, magnitude, and significance across our study period. This time variance could explain inconsistencies in the published literature to date. While meteorology weakly modulates SARS-CoV-2 transmission, daily or seasonal weather variations alone will not stave off future surges in COVID-19 cases in Brazil. Investigating how the roles of environmental factors and disease control interventions may vary with time should be a deliberate consideration of future research on the drivers of SARS-CoV-2 transmission.