Contextual factors and the COVID-19 outbreak rate across U.S. counties in its initial phase

This study examines the association of contextual factors with the COVID-19 outbreak rate across U.S. counties in its initial phase.

Contextual factors are simultaneously tested at the county- and state-level with a multilevel linear model using full maximum likelihood.

The variation between states is substantial and significant (ICC = 0.532, u ₀ = 8.20E-04, P < .001). At the state level, the cultural value of collectivism and the contextual factor of government spending are positively associated with the outbreak rate. At the county level, the racial and ethnic composition contributes to outbreak differences, disproportionally affecting black/African, native, Asian, and Hispanic Americans as well as native Hawaiians. Counties with a higher median age and a higher household income have a stronger outbreak. Better education and personal health are generally associated with a lower outbreak. Obesity and smoking are negatively related to the outbreak, in agreement with the value expectancy concepts of the health belief model. Air pollution is another significant contributor to the outbreak.

Because of a high variation in contextual factors, policy makers need to target pandemic responses to the smallest subdivision possible, so that countermeasures can be implemented effectively.