How everyday speech could transmit viral droplets

It is well known that an individual infected with the coronavirus can spread it to others through respiratory droplets projected by violent expiratory events like coughing and sneezing.

Evidence also shows that the virus can also be transmitted before these symptoms arise. The airflow generated from everyday conversations is increasingly recognized as a potent route of transmission, especially as people spend more time indoors during the fall and winter.

Using high-speed imaging of an individual producing common speech sounds, Abkarian and Stone report that the sudden burst of airflow produced from the articulation of consonants like /p/ or /b/ carry salivary and mucus droplets for at least a meter in front of a speaker.

In additional experiments, the researchers demonstrate that an ordinary lip balm reduces the droplets contained in speech-driven flows.

The research will be published in Physical Review Fluids on Friday, October 2, 2020.