Contact Tracing is Associated with Lower COVID-19 Case Fatality Rates: Evidence from 40 countries

The coronavirus disease (COVID-19) outbreak has killed over 725,000 people since its emergence in late 2019. As of early August 2020, there has been substantial variability in the policies and intensity of diagnostic efforts between countries. In this paper, we quantitatively evaluate the effectiveness of the national contact tracing policy in decreasing case fatality rates of COVID-19 in 40 countries. Our regression analyses indicate that countries that utilize comprehensive contact tracing have significantly lower case fatality rates. The association of contact tracing policy and case fatality rates is robust and observed in regression models using cross-sectional and panel data, even controlling for the number of tests conducted and non-pharmaceutical control measures adopted by governments. Our results suggest that comprehensive contact tracing is instrumental not only to curtailing transmission but also to reducing case fatality rates by early detection and isolation of secondary cases and ultimately diminishing the burden on the healthcare system and speeding the rate at which infected individuals receive the medical care they need to maximize their chance of recovery.