Operating system

Contact tracing

Outbreak

Tracing

Pathology

Virology

Case fatality rate

Isolation (microbiology)

Coronavirus

Disease

Population

2019-20 coronavirus outbreak

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)

Coronavirus disease 2019 (COVID-19)

Epidemic control

Computer security

Computer science

Infectious disease (medical specialty)

Medical emergency

Bioinformatics

Medicine

Transmission (telecommunications)

Telecommunications

Biology

Environmental health

Science

The newly emergent human virus SARS-CoV-2 (severe acute respiratory syndrome-coronavirus 2) is resulting in high fatality rates and incapacitated health systems. Preventing further transmission is a priority. We analyzed key parameters of epidemic spread to estimate the contribution of different transmission routes and determine requirements for case isolation and contact tracing needed to stop the epidemic. Although SARS-CoV-2 is spreading too fast to be contained by manual contact tracing, it could be controlled if this process were faster, more efficient, and happened at scale. A contact-tracing app that builds a memory of proximity contacts and immediately notifies contacts of positive cases can achieve epidemic control if used by enough people. By targeting recommendations to only those at risk, epidemics could be contained without resorting to mass quarantines ("lockdowns") that are harmful to society. We discuss the ethical requirements for an intervention of this kind.

Quantifying SARS-CoV-2 transmission suggests epidemic control with digital contact tracing