State-level needs for social distancing and contact tracing to contain COVID-19 in the United States
Weihsueh A. Chiu, Rebecca S. B. Fischer, Martial L. Ndeffo-Mbah
Abstract
Starting in mid-May 2020, many US states began relaxing social-distancing measures that were put in place to mitigate the spread of COVID-19. To evaluate the impact of relaxation of restrictions on COVID-19 dynamics and control, we developed a transmission dynamic model and calibrated it to US state-level COVID-19 cases and deaths. We used this model to evaluate the impact of social distancing, testing and contact tracing on the COVID-19 epidemic in each state. As of 22 July 2020, we found that only three states were on track to curtail their epidemic curve. Thirty-nine states and the District of Columbia may have to double their testing and/or tracing rates and/or rolling back reopening by 25%, while eight states require an even greater measure of combined testing, tracing and distancing. Increased testing and contact-tracing capacity is paramount for mitigating the recent large-scale increases in US cases and deaths. Using a US state-level Bayesian susceptible, exposed, infectious, removed (SEIR) compartmental model, the authors demonstrate that, in almost all states, doubling rates of contact tracing and testing while also rolling back reopening by 25–50% via social distancing can mitigate the resurgence of COVID-19.