Journal Article

Looking under the lamp-post: quantifying the performance of contact tracing in the United States during the SARS-CoV-2 pandemic

Raifman, Julia, Bayly, Henry, Murray, Eleanor J, Chakravarty, Arijit, White, Laura F, Stoddard, Madison, Van Egeren, Debra

2024

Overview

Contact tracing forms a crucial part of the public-health toolbox in mitigating and understanding emergent pathogens and nascent disease outbreaks. Contact tracing in the United States was conducted during the pre-Omicron phase of the ongoing COVID-19 pandemic. This tracing relied on voluntary reporting and responses, often using rapid antigen tests due to lack of accessibility to PCR tests. These limitations, combined with SARS-CoV-2’s propensity for asymptomatic transmission, raise the question “how reliable was contact tracing for COVID-19 in the United States”? We answered this question using a Markov model to examine the efficiency with which transmission could be detected based on the design and response rates of contact tracing studies in the United States. Our results suggest that contact tracing protocols in the U.S. are unlikely to have identified more than 1.65% (95% uncertainty interval: 1.62-1.68%) of transmission events with PCR testing and 1.00% (95% uncertainty interval 0.98-1.02%) with rapid antigen testing. When considering a more robust contact tracing scenario, based on compliance rates in East Asia with PCR testing, this increases to 62.7% (95% uncertainty interval: 62.6-62.8%). We did not assume presence of asymptomatic transmission or superspreading, making our estimates upper bounds on the actual percentages traced. These findings highlight the limitations in interpretability for studies of SARS-CoV-2 disease spread based on U.S. contact tracing and underscore the vulnerability of the population to future disease outbreaks, for SARS-CoV-2 and other pathogens.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Analysis / Antigens / Asymptomatic / Biostatistics / Contact tracing / Contact Tracing - methods / COVID-19 / COVID-19 - diagnosis / COVID-19 - epidemiology / Development and progression / Disease Outbreaks / Disease spread / Disease transmission / Diseases / Environmental Health / Epidemics / Epidemiology / Estimates / Hairdressers / Health aspects / Humans / Infectious disease epidemiology / Infectious disease transmission / Interviews / Markov chains / Markov processes / Medicine / Medicine & Public Health / Outbreaks / Pandemics / Pathogens / Polymerase chain reaction / Prevention / Public Health / Questions / SARS-CoV-2 / Severe acute respiratory syndrome coronavirus 2 / South Dakota / South Korea / Testing / Uncertainty / United States / United States - epidemiology / Upper bounds / Vaccine / Viral diseases