Speaking in indoor spaces while not wearing a mask presents the greatest risk of spreading COVID, according to a research published in the Journal of Internal Medicine.
The research describes how respiratory droplets emitted during speech can carry different amounts of virus depending on their sizes and places of origin. The researchers found that droplets of intermediate size that remain suspended in air for a few minutes pose the maximum danger, said a PTI report. They can be carried by air currents over considerable distances.
Spit droplets and more
Tiny aerosols containing the virus, emitted when speaking, linger in the air for longer than larger droplets that come from a cough or sneeze. The researchers said their study shows “solid evidence” that talking is the “dominating” source for transmission.
“We’ve all seen some spit droplets flying when people talk but there are thousands more, too small to be seen by the naked eye,” PTI quoted Adriaan Bax of the US National Institute of Diabetes and Digestive and Kidney Diseases as saying.
“When the water evaporates from such speech-generated, potentially virus-rich droplets, they float in the air for minutes, like smoke, thus putting others at risk,” said Bax, senior author of the study.
As part of their study, the researchers examined the physical and medical aspects of aerosol droplets in virus transmission. The conclusion was that airborne transmission of SARS-CoV-2 is the dominant pathway for transmitting COVID, and that unmasked speech in confined spaces is the riskiest activity of all.
“Since eating and drinking often take place indoors and typically involve loud speaking, it should come as no surprise that bars and restaurants have become the epicentre of multiple recent superspreading events,” the authors of the study said.
How to prevent spread
Next to vaccination, the emphasis should be on the use of face masks when speaking, said the authors. They further said adequate ventilation to flush out long-lived aerosols should be ensured. Else, such aerosols may accumulate in closed environments and increase the risk of more serious lower respiratory tract infections.
The researchers suggest that masks be worn in confined spaces such as offices, shops, retail outlets and homes. This can reduce the risk of infection more than eightfold if both individuals are covered.