Active Monitoring of Persons Exposed to Patients with Confirmed COVID-19 — United States, January–February 2020

TLDR

An outbreak of COVID‑19 caused by SARS‑CoV‑2 began in Wuhan in December 2019 and had spread to 36 other countries, including the United States, by February 26, 2020, with documented person‑to‑person transmission and limited sustained spread in some countries. The monitoring program sought to rapidly evaluate and care for patients, curb transmission, and elucidate transmission risk factors. State and local health departments, with CDC teams, began identifying and monitoring all persons with close contact to confirmed COVID‑19 patients on January 20. These efforts aimed to ensure rapid evaluation and care of patients, limit further transmission, and better understand risk factors for transmission.

Abstract

In December 2019, an outbreak of coronavirus disease 2019 (COVID-19), caused by the virus SARS-CoV-2, began in Wuhan, China (1). The disease spread widely in China, and, as of February 26, 2020, COVID-19 cases had been identified in 36 other countries and territories, including the United States. Person-to-person transmission has been widely documented, and a limited number of countries have reported sustained person-to-person spread.* On January 20, state and local health departments in the United States, in collaboration with teams deployed from CDC, began identifying and monitoring all persons considered to have had close contact† with patients with confirmed COVID-19 (2). The aims of these efforts were to ensure rapid evaluation and care of patients, limit further transmission, and better understand risk factors for transmission.