Spatially Refined Time-Varying Reproduction Numbers of COVID-19 by Health District in Georgia, USA, March–December 2020

Authors

Chigozie A. Ogwara, Georgia Southern University, Jiann-Ping Hsu College of Public HealthFollow
Arshpreet Kaur Mallhi, Georgia Southern University, Jiann-Ping Hsu College of Public HealthFollow
Xinyi Hua, Georgia Southern University, Jiann-Ping Hsu College of Public HealthFollow
Kamalich Muniz-Rodriguez, Georgia Southern University, Jiann-Ping Hsu College of Public HealthFollow
Jessica S. Schwind, Georgia Southern University, Jiann-Ping Hsu College of Public HealthFollow
Xiaolu Zhou, Texas Christian UniversityFollow
Jeffery A. Jones, Georgia Southern University, Jiann-Ping Hsu College of Public HealthFollow
Joanne Chopak-Foss, Georgia Southern University, Jiann-Ping Hsu College of Public HealthFollow
Gerardo Chowell, Georgia State UniversityFollow
Isaac Chun-Hai Fung, Georgia Southern University, Jiann-Ping Hsu College of Public HealthFollow

Document Type

Article

Publication Date

5-28-2021

Publication Title

Epidemiologia

DOI

10.3390/epidemiologia2020014

Abstract

This study quantifies the transmission potential of SARS-CoV-2 across public health districts in Georgia, USA, and tests if per capita cumulative case count varies across counties. To estimate the time-varying reproduction number, Rt of SARS-CoV-2 in Georgia and its 18 public health districts, we apply the R package ‘EpiEstim’ to the time series of historical daily incidence of confirmed cases, 2 March–15 December 2020. The epidemic curve is shifted backward by nine days to account for the incubation period and delay to testing. Linear regression is performed between log10-transformed per capita cumulative case count and log10-transformed population size. We observe Rt fluctuations as state and countywide policies are implemented. Policy changes are associated with increases or decreases at different time points. Rt increases, following the reopening of schools for in-person instruction in August. Evidence suggests that counties with lower population size had a higher per capita cumulative case count on June 15 (slope = −0.10, p = 0.04) and October 15 (slope = −0.05, p = 0.03), but not on August 15 (slope = −0.04, p = 0.09), nor December 15 (slope = −0.02, p = 0.41). We found extensive community transmission of SARS-CoV-2 across all 18 health districts in Georgia with median 7-day-sliding window Rt estimates between 1 and 1.4 after March 2020.

Comments

Georgia Southern University faculty members, Jessica S. Schwind, Jeffery A. Jones, and Joanne Chopak-Foss co-authored Spatially Refined Time-Varying Reproduction Numbers of COVID-19 by Health District in Georgia, USA, March–December 2020.

Recommended Citation

Ogwara, Chigozie A., Arshpreet Kaur Mallhi, Xinyi Hua, Kamalich Muniz-Rodriguez, Jessica S. Schwind, Xiaolu Zhou, Jeffery A. Jones, Joanne Chopak-Foss, Gerardo Chowell, Isaac Chun-Hai Fung. 2021. "Spatially Refined Time-Varying Reproduction Numbers of COVID-19 by Health District in Georgia, USA, March–December 2020." Epidemiologia, 2 (2): 179-197: MDPI. doi: 10.3390/epidemiologia2020014
https://digitalcommons.georgiasouthern.edu/bee-facpubs/401

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 License.