The new coronavirus was widely distributed in the air and on object surfaces in both the intensive care unit and general ward at a hospital in China, a new study published in Emerging Infectious Diseases shows.
From Feb. 19 to March 2, researchers collected swab samples from potentially contaminated objects, as well as samples from indoor air and the air outlets in the ICU and general ward of the hospital in Wuhan. The researchers tested the samples, which showed evidence of the genetic material of the new coronavirus, but do not indicate the amount of live virus in the air or on objects, if any.
The ICU housed 15 patients with severe COVID-19, and the general ward housed 24 patients with milder cases of the disease.
Researchers found that the rate of positive samples was much higher in the ICU (43.5 percent of 124 samples tested positive) than in the general ward (7.9 percent of 114 samples tested positive).
The rate of positive samples was relatively high for floor swab samples — with 70 percent of the 10 floor swab samples from the ICU and 15.4 percent of the 13 samples from the general ward testing positive. This might be "because of gravity and air flow causing most virus droplets to float to the ground," study authors wrote.
Half of the samples from the shoe soles of the ICU medical staff tested positive, which means shoe soles "might function as carriers," the authors wrote.
The rate of positive samples was also relatively high for the object surfaces that were frequently touched by medical staff or patients in the ICU and general ward.
In the ICU, the highest positive rates were for the following objects:
● Computer mice: 75 percent of eight ICU samples tested positive
● Trash cans: 60 percent of five ICU samples tested positive
● Sickbed handrail: 42.9 percent of 14 ICU samples tested positive
Researchers also collected air in the isolation ward of the ICU and general ward. The researchers obtained positive test results for 35 percent of 40 ICU samples tested, and 12.5 percent of 16 general ward samples tested.
Of 12 swabs collected from air vents in the ICU, eight (66.7 percent) tested positive, as did one of 12 (8.3 percent) air vent swabs collected from the general ward.
Fine solid particles or liquid droplets of the new coronavirus suspended in air were found in patient rooms and in physicians' office areas. Based on the detection of virus in physicians' office areas "the maximum transmission distance of SARS-CoV-2 [the novel coronavirus] aerosol might be 4 m [13 feet]," they said.