1. Coronavirus Disease 2019 (COVID-19) Transmission in the United States Before Versus After Relaxation of Statewide Social Distancing Measures.
- Author
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Tsai, Alexander C, Harling, Guy, Reynolds, Zahra, Gilbert, Rebecca F, and Siedner, Mark J
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COVID-19 , *CONFIDENCE intervals , *REGRESSION analysis , *PUBLIC health , *PRE-tests & post-tests , *DESCRIPTIVE statistics , *SOCIAL distancing , *LONGITUDINAL method - Abstract
Background Weeks after issuing social distancing orders to suppress severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission and reduce growth in cases of severe coronavirus disease 2019 (COVID-19), all US states and the District of Columbia partially or fully relaxed these measures. Methods We identified all statewide social distancing measures that were implemented and/or relaxed in the United States between 10 March and 15 July 2020, triangulating data from state government and third-party sources. Using segmented linear regression, we estimated the extent to which relaxation of social distancing affected epidemic control, as indicated by the time-varying, state-specific effective reproduction number (R t ). Results In the 8 weeks prior to relaxation, mean R t declined by 0.012 units per day (95% confidence interval [CI], −.013 to −.012), and 46/51 jurisdictions achieved R t < 1.0 by the date of relaxation. After relaxation of social distancing, R t reversed course and began increasing by 0.007 units per day (95% CI,.006–.007), reaching a mean R t of 1.16. Eight weeks later, the mean R t was 1.16 and only 9/51 jurisdictions were maintaining an R t < 1.0. Parallel models showed similar reversals in the growth of COVID-19 cases and deaths. Indicators often used to motivate relaxation at the time of relaxation (eg, test positivity rate <5%) predicted greater postrelaxation epidemic growth. Conclusions We detected an immediate and significant reversal in SARS-CoV-2 epidemic suppression after relaxation of social distancing measures across the United States. Premature relaxation of social distancing measures undermined the country's ability to control the disease burden associated with COVID-19. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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