A small study by Chinese scientists suggests that the COVID-19 virus can travel more than 13 feet in the the air.

The research, published Friday in the Centers for Disease Control and Prevention's Emerging Infectious Diseases journal, examined samples of aerosol from indoor air and air outlets in an intensive care unit and hospital ward in Wuhan, China. The areas studied held 37 virus patients.

The scientists also took swab samples from surfaces such as floors, handrails, computer mice, patient masks and shoes.

“The aerosol distribution characteristics … indicate that the transmission distance of [COVID-19] might be 4 m (meters),” the report says. “Furthermore, half of the samples from the soles of the ICU medical staff shoes tested positive. Therefore, the soles of medical staff shoes might function as carriers.”

Whether SARS-CoV-2, the virus that causes COVID-19, can be spread by aerosols remains controversial. On April 2, Dr. Harvey Fineberg told the White House studies “are consistent” with aerosolization of virus from normal breathing. But other scientists say aerosolized SARS-CoV-2 is relatively rare.

The researchers surmised the relatively high rate of positivity of the hospital's floors might be caused by gravity and air flow causing most virus droplets to float to the ground, accounting for the contamination of the shoes of the staff.

“As medical staff walk around the ward, the virus can be tracked all over the floor, as indicated by the 100% rate of positivity from the floor in the pharmacy, where there were no patients,” the researchers wrote.

The CDC says to ensure effective physical distancing, people should stay at least 6 feet apart. The World Health Organization says 3 feet should be enough.

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Mike Moffitt is an SFGATE Digital Reporter. Email: moffitt@sfgate.com. Twitter: @Mike_at_SFGate