Cross-country evidence on the association between contact tracing and COVID-19 case fatality rates

Abstract

The coronavirus disease (COVID-19) outbreak has killed over a million people since its emergence in late 2019. However, there has been substantial variability in the policies and intensity of diagnostic efforts between countries. In this paper, we quantitatively evaluate the association between national contact tracing policies and case fatality rates of COVID-19 in 138 countries. Our regression analyses indicate that countries that implement comprehensive contact tracing have significantly lower case fatality rates. This association of contact tracing policy and case fatality rates is robust in our longitudinal regression models, even after 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. Contact tracing achieves the early detection and isolation of secondary cases which are particularly important given that the peak in infectiousness occurs during the presymptomatic phase. The early detection achieved by contact tracing accelerates the rate at which infected individuals receive medical care they need to maximize their chance of recovery. In addition, the combination of reduced transmission and more rapid recovery diminishes the burden on the healthcare system which in turn ensures that the resources remain available for individuals who do become infected.

Pandemic Prevention: Lessons from COVID-19

“…[31]). Yalaman et al [32] suggest that comprehensive contact tracing is an instrumental approach not only for curtailing transmission but also to reduce case fatality rates. In fact, the combination of reduced transmission and more rapid recovery reduces the burden on healthcare system, which can save resources for individuals that are infected in the future.…”

Lessons Learned From COVID-19 Contact Tracing During a Public Health Emergency: A Prospective Implementation Study

“…In East Asia, e.g., contact tracing was rapidly and effectively adapted for COVID-19 thanks to early and massive political and financial investments, informed by prior experiences with Severe Acute Respiratory Syndrome (SARS) ( 5 ) and Middle East Respiratory Syndrome (MERS) ( 6 ) and largely receptive societies. When combined with other preventive measures including physical distancing, universal masking, and digital tracking, contact tracing for COVID-19 has been shown to reduce the effective reproductive number (R e ) ( 7 ), secondary attack rates ( 8 ) and case fatality rates ( 9 , 10 ) and to contain outbreaks and generalized epidemics in diverse settings ( 10 – 12 ). Nevertheless, contact tracing has not proven effective everywhere ( 13 , 14 ), and many have questioned its overall usefulness in the recent pandemic ( 15 ).…”

Integrated PCR testing and extended window contact tracing system for COVID-19 to improve comprehensiveness and speed

“…Despite ubiquitous rollout of contact tracing to counteract the spread of COVID-19, few countries have been spared from widespread community transmission, highlighting the need for more effective tracing strategies 1,2 . In the context of the KU Leuven testing and contact tracing program, we have opted to implement bidirectional contact tracing by introducing a combination of an extended contact tracing window and testing of contacts both immediately and 7 days after exposure to an index case.…”