With coronavirus: Exactly what is ‘a close contact’?

Misleading info cause for concern

Anna Maria Barry-Jester California Healthline | 2/14/2020, midnight

Even as U.S. authorities have taken the drastic steps of quarantining residents returning from China, and temporarily banning foreign visitors who recently traveled to affected Chinese regions, they have urged the vast majority of U.S. residents to go about their regular activities.

But there are exceptions. People who returned from China on or after Feb. 3 have been formally quarantined or asked to stay home. And behind the scenes, local public health officials have launched painstaking efforts to reach “close contacts” of people with confirmed cases of the virus, dubbed 2019-nCoV, asking them to self-quarantine and submit to ongoing monitoring.

So what exactly is a “close contact”? It’s an intuitive-sounding term, but has a clinical definition that varies by infectious disease. The deadly measles virus, for example, can linger in a place for hours, in the air and on surfaces, after an infected person has spent time there. Coronaviruses are generally passed through droplets, requiring close physical contact with a sneeze or other body secretion.

How a virus is spread, and the severity of the illness it causes, determines how public health departments decide how many people are at risk of contagion and how many resources go into notifying them. When it comes to measles, officials broadly publicize every known location an infected person frequented in the days before being diagnosed, and try to track down people who came in contact with that patient and who have not been vaccinated.

For the new coronavirus, guidelines from the federal Centers for Disease Control and Prevention define “close contact” as anyone who has been within six feet of a person infected with the virus for a “prolonged period of time,” as well as those who have had direct contact with the infected person’s secretions. These guidelines are then interpreted by local public health departments.

The European Union’s health agency offers a descriptive definition: someone living in the same household as a patient; someone who has had face-to-face contact with or been in a closed environment with a patient; or a health care worker directly caring for a patient. It’s also any plane (and by extension, train or bus) passenger sitting within two seats, in any direction, of an infected person. The World Health Organization flags health care providers and household members, as well as anyone who has been within 3 feet of a confirmed case once the infected person had symptoms.

Translating those guidelines to real people and their daily movements is at the heart of what public health departments around the country do for any infectious disease. Local investigators work with patients to find out where they were and what they did in the days before they were diagnosed. They identify anyone who might be at risk for infection, track them down and help monitor their health. Depending on how close the contact was, health officials may ask the contact to temporarily stay away from others.

As of Monday, tens of thousands of people in mainland China were confirmed to have the disease, and hundreds had died. But in the U.S, there have been just a dozen cases so far, nearly all among people who recently returned from the country of 1.4 billion. State and federal health officials stress that the risk of getting the virus in this country remains low.