Most COVID-19 patients don't know who infected them, CDC survey finds
A survey published by the Centers for Disease Control and Prevention found that 54% of people infected with coronavirus were unable to pinpoint who may have infected them.
Experts said the survey results underscore an important point: Community and asymptomatic spread is alive and well, which makes contact tracing especially difficult during the pandemic.
More than half of the 350 respondents couldn’t identify a person with COVID-19 with whom they had close contact in the previous two weeks.
“If people don’t know where they got (COVID-19) and they can’t identify it at home or from a family member, they’re getting it from the community,” said Len Horovitz, pulmonary specialist at Lenox Hill Hospital in New York City, suggesting people unknowingly get infected outside their homes, possibly in indoor establishments without masks or social distancing.
Dr. Joshua Barocas, assistant professor of medicine at the Boston University School of Medicine, said the CDC survey highlights the prevalence of asymptomatic disease and spread.
“It’s very concerning,” he said during a media briefing hosted by the Infectious Disease Society of America. “We have seen asymptomatic disease is incredibly common, not just in what we classify as low-risk populations but also high-risk populations.”
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Contact tracing and testing needed
Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, told CNN Monday that contact tracing in the USA isn’t going very well.
The World Health Organization breaks down contact tracing into three basic steps: identification, listing and follow-up.
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A patient who tests positive for the virus is asked whom he or she contacted, such as family members, colleagues, friends or health care providers. Then tracers attempt to identify and reach out to all those who came into contact with the COVID-19-positive patient. Regular follow-ups should be conducted with all contacts to monitor for symptoms.
“What you’re seeing is community-based spread where 20 to 40% of the people who are infected don’t have any symptoms,” Fauci said. “So the standard, classic paradigm of identification, isolation, contact tracing doesn’t work no matter how good you are because you don’t know who you’re tracing.”
The nation's top infectious disease expert said the federal government is considering “blanketing these communities with tests” to get a clear picture of infection.
Risks abound
Even in bars and restaurants where social distancing is observed, Horovitz said, air ventilation can carry respiratory droplets or aerosols that contain virus.
In a separate study, the CDC published initial findings of an outbreak linked to the airflow in a Guangzhou, China, restaurant. Over the course of 12 days, nine people who dined at the restaurant Jan. 24 fell ill as a result of another patron with a COVID-19 infection, the authors determined.
Within five days, three people sitting at the infected patron's table were infected along with another below the air conditioner. Of the 91 people in the restaurant during that hour, only those at tables in the way of the air conditioner’s airflow contracted the virus.
Dr. Ricardo Franco, assistant professor of medicine at the University of Alabama-Birmingham, said the culprit may not be a person but a contaminated surface – although most experts said this type of infection is relatively rare.
“I think the study really illustrates the tough reality that for (some) people getting infected, your contact is going to be your anonymous door handle or gas pump handle or that indoor environment,” Franco said.
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Health and patient safety coverage at USA TODAY is made possible in part by a grant from the Masimo Foundation for Ethics, Innovation and Competition in Healthcare. The Masimo Foundation does not provide editorial input.
Follow Adrianna Rodriguez on Twitter: @AdriannaUSAT.
This article originally appeared on USA TODAY: Most COVID-19 patients don't know who infected them, CDC survey finds
