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Author Spotlight: Advancements in Multiplex Detection of Respiratory Viruses
Published on: November 10, 2023
SARS-CoV-2 Transmission Potential and Policy Changes in South Carolina, February 2020 - January 2021
Margaret R Davies1, Xinyi Hua1, Terrence D Jacobs1
1Department of Biostatistics, Epidemiology and Environmental Health Sciences, Jiann-Ping Hsu College of Public Health, Georgia Southern University, Statesboro, Georgia, USA.
Introduction:
We aimed to examine how public health policies influenced the dynamics of coronavirus disease 2019 (COVID-19) time-varying reproductive number (R ) in South Carolina from February 26, 2020, to January 1, 2021.
Methods:
COVID-19 case series (March 6, 2020, to January 10, 2021) were shifted by 9 d to approximate the infection date. We analyzed the effects of state and county policies on R using EpiEstim. We performed linear regression to evaluate if per-capita cumulative case count varies across counties with different population size.
Results:
R shifted from 2-3 in March to <1 during April and May. R rose over the summer and stayed between 1.4 and 0.7. The introduction of statewide mask mandates was associated with a decline in R (-15.3%; 95% CrI, -13.6%, -16.8%), and school re-opening, an increase by 12.3% (95% CrI, 10.1%, 14.4%). Less densely populated counties had higher attack rates (P < 0.0001).
Conclusions:
The R dynamics over time indicated that public health interventions substantially slowed COVID-19 transmission in South Carolina, while their relaxation may have promoted further transmission. Policies encouraging people to stay home, such as closing nonessential businesses, were associated with R reduction, while policies that encouraged more movement, such as re-opening schools, were associated with R increase.
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