This review of the literature found singing within choirs is associated with an increased risk of transmission of COVID-19, but a combination of strategies will provide the best protection from COVID-19 transmission during choir rehearsals and performances.
Major Findings: Five Point Summary
1: Singing is not free of risk.
Louder singing and speaking has been associated with increased emissions of airborne particles.
Our review of the literature found singing within choirs is associated with an increased risk of transmission of COVID-19, but a combination of strategies will provide the best protection from COVID-19 transmission during choir rehearsals and performances.
2: Agreement on types of transmission
Although the routes of transmission in choir settings are not fully understood, there is agreement that the routes include direct person-to-person contact, and indirect transmission through droplets and aerosols and contact with object or surfaces (fomites).
Our recommendations are divided into three categories—Ventilation (controlling airborne particles), Hygiene (contact with infected surfaces) and Physical Space (direct person-to-person contact)—however, there is not agreement on the relative importance of each one.
3: Multiple Control Measures likely to be the most effective
The scientific research surrounding singing and COVID-19 is emerging and fragmented, meaning there is not yet agreement on the risks of singing and the effectiveness of control measures.
It has emerged from the review that until further primary research specific to choir settings has been undertaken, employing as many of the control measures as possible will increase the chances that they will be effective and provide choirs in communities with low COVID-19 prevalence with the best protection from COVID-19 transmission during choir rehearsals.
In the overseas events reported, the common feature was the absence of a number of the control measures we now understand to be effective.
Louder singing and speaking is associated with increased emission of aerosols and individual variability of airborne particle emission is high. We need to take aerosols seriously in a choral setting—think of them like the dissipation of incense or smoke that we can see.
Recirculated air was noted in outbreaks overseas and effective ventilation is a plausible control measure for removing infected aerosols from a space.
It is recommended that choirs work with their venues and ventilation specialists to better understand the effectiveness of ventilation systems and provide advice on airflow.
Wellbeing is an important part of the health mix and ACN encourages choirs to take the wellbeing of their participants into account when developing a COVID-safe strategy and to reflect on the effects of not being able to sing with other people.
Before COVID-19, we could only speculate on what life would be like without choir, and knowing we had a once-in-a-lifetime window to fine out, ACN put a single survey question to the network during 2020— “Now that you’ve have time to reflect on what life is like without choir, what do you miss?”.
The results overwhelmingly revealed that being deprived of singing with other people made a significant impact on the psychological, physical and emotional wellbeing of our choral community.
This single expression powerfully reflects the feeling of the greater network: “Singing fills me with joy and positivity. Without singing, I am much less. I miss the physical ‘workout’ of choir – it helps keep your brain and your body fit”.
An outbreak in a choir rehearsal in Spain  illustrates the problem well for choirs. On 11 September 2020, 41 members of the River Troupe Gospel attended a rehearsal leading up to their open-air performance two days later. The choir complied with risk mitigation measures at the rehearsal including temperature checks on arrival—hand washing, physical distancing, and masks. However, the venue’s windows were closed to avoid moths and mosquitoes and the air conditioning had been switched on because it was hot. One singer tested positive on the 13th September and all choir members and their close contacts isolated from that date. Thirty of the 41 singers developed COVID-19.
 Associated Press 2020, 'Choir practice in Spain infects 30 of 41 members with virus', ABC News, 24 September 2020, viewed 7 October 2020