How is the US Tracking Coronavirus Contacts?

As the US Centers for Disease Control and Prevention (CDC) prepares for more cases of novel coronavirus (COVID-19) linked to community spread, active monitoring of individuals exposed to patients with confirmed COVID-19 will be essential to mitigating the impact of the virus

A new CDC Morbidity and Mortality Weekly Report article contains details on public health efforts that are being employed to track contacts of people with COVID-19. Monitoring efforts are aimed at ensuring the rapid diagnosis and care of patients, limiting further spread of the viruses, and improving clinical understanding of risk factors for transmission.

The first case of COVID-19 in the United States was diagnosed on January 20^th, in Washington State.

“On January 20^th, 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,” authors of the report wrote.

On January 31^st, US Department of Health and Human Services Secretary Alex Azar signed a public health emergency declaration. Soon after, the US Food and Drug Administration (FDA) issued emergency authorization for a COVID-19 diagnostic which has not yet gone through the FDA approval process, allowing any CDC qualified lab to use the test.

As of February 26^th, 12 of the COVID-19 cases diagnosed in the United States were believed to be travel related. An additional 3 cases were known at the time in patients without travel history, 2 of which were close household contacts of cases with travel history to China.

The confirmed cases were isolated in the hospital if medically necessary, or otherwise kept at home. A total of 445 contacts were monitored in connection with the first 10 patients. Of these individuals, 222 were health care professionals.

Monitoring was conducted by daily to assess possible symptoms via telephone, text, or in-person visits. The contacts of confirmed cases were monitored actively for 14 days. During this period, 54 developed symptoms which put them in the “under investigation” category and prompted testing. Of these, 2 household members of patients with COVID-19 tested positive for the virus.

The contacts of these 2 individuals were monitored. Out of 146 monitored contacts, none tested positive for COVID-19 despite 18 developing concerning symptoms which prompted testing.

However, since these early cases were monitored there have been cases which appear to point to community spread.

“Since February 28^th, an increasing number of newly diagnosed confirmed and presumptive COVID-19 cases have been in patients with neither a relevant travel history nor clear epidemiologic links to other confirmed COVID-19 patients,” the authors of the report wrote.

As of March 3^rd, 9 US COVID-19 associated deaths occurred among individuals in Washington state.

While individual monitoring is an important part of early containment efforts, it’s possible that as more cases are reported, the strategy of close monitoring will need to shift.

“At some point, we’re going to be shifting our approach from counting every case to focusing on outbreaks, perhaps cases that occur at hospitals, and we won’t be able to do the kind of individual case follow up and case management that we’re doing early on during this so called containment phase of the epidemic," Washington public health officer Jeff Duchin, MD, said.

For the most recent counts in the COVID-19 outbreak in the United States and abroad, visit the Contagion® Outbreak Monitor.