A new major research project conducted by Imperial College London, University of Bristol, Wexham Park Hospital, Lewisham and Greenwich NHS Trust and Royal Brompton Hospital has explored the impact of singing, talking and shouting on the spread of Covid-19.
The trial saw a large group of 25 professional performers (including six musical theatre artists) speaking, singing, breathing and coughing, while another experiment saw the same individuals singing and speaking "Happy Birthday" between the decibel (dB) ranges of 50–60, 70-80 and 90-100 dB. Researchers then tracked the amounts of aerosols and droplets (up to 20 µm diameter) generated by the activities.
What made these tests special was that they were carried out in "zero aerosol background" settings, whereby it is possible to distinguish aerosols produced by subjects from ambient particles in the environment.
Initial findings based on early data suggest that there is a "steep rise" when performers speak or sing louder than usual, but that singing does not produce very substantially more aerosol than speaking at a similar volume (shouting and belting will therefore be riskier). The genre of the song being sung makes no difference, according to the results.
The study, which has only just released its preliminary findings, is supported by Public Health England and the Department for Digital, Culture, Media and Sport (DCMS). It encourages producers to think about increasingly ventilation and use as much amplification as possible for those on stage.
The report advises: "Musical organisations could consider treating speaking and singing equally, with more attention focused on the volume at which the vocalisation occurs, the number of participants (source strength), the type of room in which the activity occurs (i.e. air exchange rate) and the duration of the rehearsal and period over which performers are vocalising.
"Indeed, based on the differences observed between vocalisation and breathing and the likely difference in the number of performers and audience members in many venues, singers may not be responsible for the greatest production of aerosol during a performance and ways to ensure adequate ventilation in the venue may be more important than restricting a specific activity."
Culture Secretary Oliver Dowden said: "I know singing is an important passion and pastime for many people who I'm sure will join me in welcoming the findings of this important study.
"We have worked closely with medical experts throughout this crisis to develop our understanding of Covid-19, and we have now updated our guidance in light of these findings so people can get back to performing together safely."
While Dowden has described singing as a 'passion and pastime', for many it is a vital source of income, particularly in a time when job opportunities have been limited while the pandemic continues.
Jonathan Reid, director of ESPRC Centre for Doctoral Training in Aerosol Science and professor of Physical Chemistry in the School of Chemistry at the University of Bristol and a corresponding author on the paper, said: "The study has shown the transmission of viruses in small aerosol particles generated when someone sings or speaks are equally possible with both activities generating similar numbers of particles."