Early and massive testing saves lives: COVID-19 related infections and deaths in the United States during March of 2020

To optimize epidemiologic interventions, predictors of mortality should be identified. The US COVID-19 epidemic data -reported up to 3-31-2020- were analyzed using kernel regularized least squares regression. Six potential predictors of mortality were investigated: (i) the number of diagnostic tests performed in testing week I; (ii) the proportion of all tests conducted during week I of testing; (iii) the cumulative number of (test-positive) cases through 3-31-2020, (iv) the number of tests performed/million citizens; (v) the cumulative number of citizens tested; and (vi) the apparent prevalence rate, defined as the number of cases/million citizens. Two metrics estimated mortality: the number of deaths and the number of deaths/million citizens. While both expressions of mortality were predicted by the case count and the apparent prevalence rate, the number of deaths/million citizens was {approx}3.5 times better predicted by the apparent prevalence rate than the number of cases. In eighteen states, early testing/million citizens/population density was inversely associated with the cumulative mortality reported by 31 March, 2020. Findings support the hypothesis that early and massive testing saves lives. Other factors -e.g., population density-may also influence outcomes. To optimize national and local policies, the creation and dissemination of high-resolution geo-referenced, epidemic data is recommended.