US health officials on Wednesday redefined what counts as close contact with someone who has COVID-19 to include shorter but repeated meetings.
For months, the United States Centers for Disease Control and Prevention said that close contact meant spending a solid 15 minutes less than two meters away from someone who tested positive for coronavirus. On Wednesday, the CDC switched to a total of 15 minutes or more – so shorter but repeated contacts, which add up to 15 minutes over a 24-hour period now count as close contact.
The CDC advises anyone who has been in close contact with a COVID-19 patient to be quarantined for two weeks.
The move could prompt health departments to track contacts in cases where an exposure may have been considered too brief, said Dr. William Schaffner, an infectious disease specialist at Vanderbilt University.
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It also serves to note that the coronavirus can spread more easily than many people realize, he said.
The change in definition was triggered by a study of a 20-year-old Vermont correctional officer who was diagnosed with coronavirus in August.
The guard, who wore a mask and goggles, had several brief meetings with six transferred prisoners before the test results showed they were positive.
Sometimes prisoners wore masks, but there were meetings at cell doors or in a recreation room where prisoners did not wear masks, the report said.
An investigation that analyzed video footage concluded that the guard’s brief interactions totaled 17 minutes during an eight-hour shift.
In a statement, CDC officials said the case again highlights the importance of wearing masks to prevent transmission.