How do you catch or spread the coronavirus? Much has been said about keeping six feet away and avoiding someone’s cough or sneeze. That’s fine, but additional evidence is surfacing about how the virus is transmitted, a key question for reopening decisions. Studies drawn from completed contact tracing — tracking down all those an infected person came into contact with — are showing that sustained, close contacts and close quarters are the biggest risks.
Dr. Muge Cevik, a scientist at the School of Medicine, University of St. Andrews, who examined a series of contact tracing studies, found increased rates of infection in enclosed and connected environments, including households, long-term-care facilities, churches, public transit and homeless shelters, among others. She said casual, short interactions appear not to be main drivers of the pandemic, but family and friends are.
For example, 2,147 close contacts of 157 coronavirus cases were examined in Ningbo, Zhejiang province, south of Shanghai. The researchers found higher risks of infection for friends, family and relatives; also, higher rates of infection among those living with the infected person or taking the same transit or dining together. In another China study, based in Shenzhen, 1,286 close contacts of 391 virus cases were tracked; again the finding was that “household contacts and those traveling with a case were at higher risk of infection.”