Can Coronavirus Be Transmitted Simply by Talking?

What the experts say

The new coronavirus is known to spread when an infected person coughs or sneezes, which releases large respiratory droplets. Those droplets can land in the mouths or noses of people within 6 feet, or on a surface or object nearby, according to the Centers for Disease Control and Prevention. But some scientific experts say the virus may be able to spread via even smaller droplets that are released when an infected person talks or breathes.

“Currently available research supports the possibility that SARS-Cov-2 could be spread via bioaerosols generated directly by patients’ exhalation,” said Harvey Fineberg, MD, PhD, president of the National Academy of Medicine, in an April 1 letter to the White House Office of Science and Technology Policy.

Aerosols are tiny particles that travel through the air. People actually emit a lot of these particles during normal breathing and speaking, according to William Ristenpart, PhD, a professor of chemical engineering at the University of California, Davis. In fact, a 2019 paper by Ristenpart and his colleagues found that the louder a person speaks, the more particles are emitted. And some people are “superemitters” who give off up to 10 times as many particles as others.

If the coronavirus can spread through these smaller droplets, it could explain why the coronavirus seems to be so contagious, and why people without symptoms can spread the virus.

“Asymptomatic and pre-symptomatic individuals, by definition, do not cough or sneeze to any appreciable extent,” Ristenpart says in a new editorial in the scientific journal Aerosol Science & Technology. “This leaves direct or indirect contact modes and aerosol transmission as the main possible modes of transmission.”