A cough or sneeze by a flu patient may be enough to spread the virus to people standing up to 6 feet away, farther than previously shown, according to a study that highlights the risk to health care workers.

Researchers at Wake Forest School of Medicine in North Carolina looked at 94 patients with flu-like symptoms who had visited the emergency room or a clinic at Wake Forest Baptist Medical Center for a checkup during the 2010-2011 flu season. The researchers swabbed the noses of the participants and took air samples from 1, 3, and 6 feet away. They also counted the number of coughs and sneezes and had patients fill out a survey about their symptoms.