Singapore — Landmark findings from a National University of Singapore (NUS) study show that talking and singing can also spread Covid-19.
Researchers at NUS revealed that Covid-19 particles could be aerosolised by an infected person during talking and singing.
They found that fine aerosols (less than five micrometres) generated from these two activities contains more viral particles than coarse aerosols (more than five micrometres).
The study involved 22 Covid-19 positive patients admitted to the National Centre for Infectious Diseases (NCID) from Feb to Apr 2021.
NCID was the research site chosen for the study.
The participants were required to perform three different expiratory activities on the same day, involving 30 minutes of breathing, 15 minutes of talking in the form of reading aloud passages from a children’s book and 15 minutes of singing different songs with rest in between activities.
The exercises were carried out using a specially designed exhalation collection equipment known as the Gesundheit-II.
It had a cone that served as the ventilation hood where the air is continuously drawn around the participant’s head, allowing for the collection of expiratory particles.
“We observed that Covid-19 patients who are early in the course of illness are likely to shed detectable levels of Covid-19 in respiratory aerosols,” said project co-leader Dr Kristen Coleman from Duke-NUS Medical School.
“However, person-to-person variation in virus emission was high. Some patients surprisingly released more virus from talking than singing.”
“Through the coordinating efforts of one of our resident doctors, Dr Sean Ong, and the support of our nursing team and patients, we were able to study key high-risk activities like talking and singing while ensuring the safety of the patients and staff involved,” noted Dr Mark Chen, Head, NCID Research Office, National Centre for Infectious Diseases.
The result provides direct measurements to show that besides respiratory droplets, virus particles emitted in exhaled breath and vocalisation activities are likely important mechanisms for transmitting Covid-19, he added.
The researchers concluded that the fine respiratory aerosols might play a significant role in Covid-19 transmission, especially in an indoor environment. Hence, it should be considered when planning infection prevention measures, noted an NUS press release on Wednesday (Aug 11).
“Although our attempts to grow infectious virus in cell culture were unsuccessful, our studies can provide an important baseline to guide infection prevention activities,” explained Professor Paul Tambyah from the NUS Yong Loo Lin School of Medicine, who is one of the co-authors of the research paper.
He noted that the findings could be applied in situations involving singing, safe distancing among singers, as well as the averting and filtering of airflow from choir to audience by deploying air curtains.
“For situations involving talking, determining airflow patterns and minimising exposure through seating and furniture configurations, distancing, and air movement alteration, such as fans, including desk fans are practical options that can be taken to lower the risk of SARS-CoV-2 transmission,” said Dr Tambyah.
The study was first published online in the journal Clinical Infectious Diseases on Aug 6.
Within a day of its publication, the paper was ranked among the top five per cent of all research outputs scored by data science company Altmetric and was given one of the highest attention scores after different factors, like the relative reach from social media sites, blogs, policy documents, and more, were taken into account, said NUS. /TISG
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