Tracing the First U.S. COVID-19 Contacts: 445 People Watched, Two Tested Positive

When COVID-19 first reached the United States, public health workers set out to find and watch everyone who had been close to each patient. From January 20, 2020, state and local health departments, with CDC teams, identified the close contacts of every confirmed case and checked on them daily. For the first 10 patients whose infections were linked to travel, that meant 445 people — and in the end, only two of them were found to be infected.

Who the contacts were

As of February 26, 2020, the United States had 12 travel-related cases, three cases in people who had not traveled (two of them household contacts) and 46 among repatriated U.S. citizens. The first 10 travel-related patients had between 1 and 201 close contacts each from the day their symptoms began.

Fourteen days of checking

Local health departments contacted each person daily — by phone, text or in person — for 14 days after their last exposure, asking about fever and other symptoms. Fifty-four contacts (12 percent) developed new or worsening symptoms that raised concern and were tested. Two tested positive, both household members of patients, and both had been close to the patient before the diagnosis and were separated from them afterward.

Five household members who stayed exposed while their relative was isolated at home did not test positive. The two secondary cases had 146 contacts of their own; 18 developed symptoms and were tested, and all were negative — no third generation of cases was found.

What it meant — then

Despite intensive follow-up, no sustained spread of symptomatic infection was seen among the close contacts of the first 10 travel-related patients. By February 28, though, a growing number of new U.S. cases had no travel history and no clear link to known patients. The report stressed infection control by patients, their households and their health care providers, together with contact tracing, to slow community spread.

Sources

Based on "Active Monitoring of Persons Exposed to Patients with Confirmed COVID-19 — United States, January–February 2020," by Rachel M. Burke, Claire M. Midgley, Melissa A. Rolfes and colleagues from CDC and state and local health departments, Morbidity and Mortality Weekly Report (Early Release, March 3, 2020), Centers for Disease Control and Prevention; a work of the United States government in the public domain.