County-Level 14-Day COVID-19 Case Trajectories


The Centers for Disease Control and Prevention has specified that a key gating indicator for relaxing community-level COVID-19 mitigation measures is a downward trajectory of documented cases during a 14-day period. This data brief uses data from USAFacts to look at the number of new confirmed cases in metropolitan, nonmetropolitan, and noncore counties from the two-week period May 3, 2020 – May 16, 2020.

The trajectory patterns over the two-week period are somewhat similar in all three classifications of county with substantial proportions of counties seeing approximately the same number of cases, or notable decreases or increases in new confirmed cases. The proportion of counties seeing any decreases or notable decreases in the number of COVID-19 cases exceeded the proportion seeing any or notable increases. But 20.1% of all counties saw an increase in the number of reported cases. Of potentially larger concern is that 22.2% of counties with any cases during the period saw a notable increase (25% or more) in the number of cases. A further concern is the number of counties where the count of confirmed COVID-19 cases increased 100% or more (15.0% of all counties). Note that some of these dramatic percentage increases can be driven by relatively low changes in the number of new cases (e.g., in counties with a relatively small number of cases during the first week of the period).

RUPRI Center for Rural Health Policy Analysis
Fred Ullrich, Keith Mueller