A study published recently in the medical journal JAMA found that 41 percent of the first 138 patients diagnosed at one hospital in Wuhan, China, were presumed to be infected in that hospital, according to an article on the CNN website.
Most of the spread doesn't appear to have been the result of a "super-spreader event," in which a single patient transmits infection to many other people.
Instead, many health care workers and many patients got infected in many parts of the hospital.
Because there was a broad spectrum of infection and only patients who were sick were tested, it's possible that there was even more transmission in the hospital.
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