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Fine aerosols emitted while talking and singing may play an important role in transmission of Covid-19, according to a new study led by researchers from the National University of Singapore (NUS).

The team found that severe acute respiratory syndrome coronavirus (SARS-CoV-2), which is the virus that causes Covid-19, can be spread through airborne particles by an infected person during talking and singing.

According to NUS, while previous studies have established the relative amount of particles produced through similar activities, this is apparently the first study that quantifies and compares the amount of Covid-19 particles in aerosols generated through breathing, talking and singing.

Some people may release more virus particles from talking than singing

The study involved 22 Covid-19 positive patients, who were admitted to the National Centre of Infectious Diseases (NCID) between February to April 2021.

By making the participants do three separate expiratory activities on the same day, namely breathing, talking, and singing, the researchers made a number of observations.

For example, they observed that Covid-19 patients who are early in the course of illness are likely to shed detectable levels of Covid-19 particles while breathing, but the person-to-person variation was high.

"Some patients surprisingly released more virus from talking than singing," said project co-leader Kristen Coleman from Duke-NUS Medical School.

While it's been difficult thus far to directly show how Covid-19 particles can be transmitted, the research team was able to study high risk activities like talking and singing, providing direct measurements to show that despite respiratory droplets, virus particles emitted in exhaled breath and vocalisation activities are "likely important mechanisms" for spreading Covid-19.

The findings of the study demonstrated that exposure to fine-particle aerosols needs to be mitigated, especially in indoor environments, in order to reduce the spread of Covid-19.

Methods such as universal masking, physical distancing, increased room ventilation, more efficient filtration and appropriately applied air-cleaning technologies were recommended by the study.

The research team also recommended a multi-layered approach of control measures to decrease the risk of airborne Covid-19 transmission.

“In situations involving singing, safe distancing among singers, as well as the averting and filtering of airflow from choir to audience, such as by deploying air curtains, are important considerations," said project leader Associate Professor Tham Kwok Wai.

Plan to conduct similar experiments for Delta variant

In light of the recent Covid-19 variants, especially the Delta variant, which has been reported to be more infectious, the researchers plan to use the same methods to determine if the aerosol viral load associated with the new variants is higher than previous strains.

They are also looking to establish the infectiousness of live virus particles emitted through talking by infected persons, given that talking is the most common community activity.

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Top image via NUS.