TY - JOUR
T1 - SARS-CoV-2 Transmission Potential and Policy Changes in South Carolina, February 2020-January 2021
AU - Davies, Margaret R.
AU - Hua, Xinyi
AU - Jacobs, Terrence D.
AU - Wiggill, Gabi I.
AU - Lai, Po Ying
AU - Du, Zhanwei
AU - Debroy, Swati
AU - Robb, Sara Wagner
AU - Chowell, Gerardo
AU - Fung, Isaac Chun Hai
N1 - Publisher Copyright:
© 2022 The Author(s). Published by Cambridge University Press on behalf of Society for Disaster Medicine and Public Health.
PY - 2023/8/4
Y1 - 2023/8/4
N2 - Introduction: We aimed to examine how public health policies influenced the dynamics of coronavirus disease 2019 (COVID-19) time-varying reproductive number (Rt) 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 Rt using EpiEstim. We performed linear regression to evaluate if per-capita cumulative case count varies across counties with different population size. Results: Rt shifted from 2-3 in March to <1 during April and May. Rt rose over the summer and stayed between 1.4 and 0.7. The introduction of statewide mask mandates was associated with a decline in Rt (-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 Rt 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 Rt reduction, while policies that encouraged more movement, such as re-opening schools, were associated with Rt increase.
AB - Introduction: We aimed to examine how public health policies influenced the dynamics of coronavirus disease 2019 (COVID-19) time-varying reproductive number (Rt) 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 Rt using EpiEstim. We performed linear regression to evaluate if per-capita cumulative case count varies across counties with different population size. Results: Rt shifted from 2-3 in March to <1 during April and May. Rt rose over the summer and stayed between 1.4 and 0.7. The introduction of statewide mask mandates was associated with a decline in Rt (-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 Rt 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 Rt reduction, while policies that encouraged more movement, such as re-opening schools, were associated with Rt increase.
KW - COVID-19
KW - epidemiology
KW - mask mandate
KW - nonpharmaceutical interventions
KW - reproduction number
UR - http://www.scopus.com/inward/record.url?scp=85136244540&partnerID=8YFLogxK
U2 - 10.1017/dmp.2022.212
DO - 10.1017/dmp.2022.212
M3 - Article
C2 - 35924560
AN - SCOPUS:85136244540
SN - 1935-7893
VL - 17
JO - Disaster Medicine and Public Health Preparedness
JF - Disaster Medicine and Public Health Preparedness
IS - 10
M1 - e276
ER -
