Nursing

2019-20 coronavirus outbreak

Biology

Public health

Computer security

Virology

Descendant

Telecommunications

Computer science

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

Outbreak

Coronavirus disease 2019 (COVID-19)

Physics

SAFER

Astronomy

Geography

Infectious disease (medical specialty)

Medicine

Transmission (telecommunications)

Pandemic

Disease

Public health interventions

Pathology

Nature Communications

Evidence-based public health approaches that minimize the introduction and spread of new SARS-CoV-2 transmission clusters are urgently needed in the United States and other countries struggling with expanding epidemics. Here we analyze 247 full-genome SARS-CoV-2 sequences from two nearby communities in Wisconsin, USA, and find surprisingly distinct patterns of viral spread. Dane County had the 12 th known introduction of SARS-CoV-2 in the United States, but this did not lead to descendant community spread. Instead, the Dane County outbreak was seeded by multiple later introductions, followed by limited community spread. In contrast, relatively few introductions in Milwaukee County led to extensive community spread. We present evidence for reduced viral spread in both counties following the statewide “Safer at Home” order, which went into effect 25 March 2020. Our results suggest patterns of SARS-CoV-2 transmission may vary substantially even in nearby communities. Understanding these local patterns will enable better targeting of public health interventions.

Revealing fine-scale spatiotemporal differences in SARS-CoV-2 introduction and spread