By Jerry Hui, Director of Choral Activities, University of Wisconsin-Stout
As we learn more about the virus SARS-CoV-2, there are more discussions in the news, social media, blogs, and other places that cite scientific research. Some research is relevant, some is not; much is misinterpreted. Sometimes anecdotes are passed off as generalized observation themselves, or oddly as a way to disprove general observation; none excites more heated arguments than the case study of the Skagit Valley Chorale in Washington (Hamner et al., 2020), where this single case either proves or disproves the danger of singing.
In other words, it can be dizzying to follow, at a time we need science for answers.
This article tracks and summarizes the primary research on singing and choral teaching, in order to provide scientific evidence for organizations in an uncertain time.
Disclaimer: summaries and brief annotations are my personal understanding. It is not meant to be a prescription or recommendation. And because science continues to learn more about this virus even after this article is published, check back to the live version of this document for updates. As always, consult with CDC, state, county, and local health officials for best practices.
Concerns About Singing
Because singing is rarely isolated as an activity to be studied, we have to rely on related studies on breathing and speaking. Existing research infers that singing is a high-risk activity that may lead to mass infection events.
Studies of tuberculosis have shown that singing is on par with coughing in terms of generating droplets with similar infection potential (Bates, J.H., Potts, W.E., et al., 1965; Loudon and Roberts, 1968). Singing in general emits more droplets than speaking through prolonged use of vowels (Asadi, S., Wexler, A. et al., 2020). The louder the volume, the more aerosol material is emitted (Asadi, S., Wexler, A. et al., 2019). Other respiratory activities may emit infectious material just as effectively as coughing/sneezing if the virus lives in the airways, which SARS-CoV-2 does (Patterson, B., Wood, R., 2019).
Room Setup
Singing outdoors is likely low-risk (Qian, H., Miao, T., et al., 2020).
Meanwhile, in the absence of proper ventilation, droplets from speech are shown to sustain in the room long afterwards (Stadnytskyi, V., Bax, C., et al., 2020). This means that our traditional mode of rehearsals, where singers congregate inside a rehearsal room, may further increase the risks involved.
If meeting indoors, increased natural ventilation is highly recommended (Morawska, L., Cao, J., 2020). Upper-room UV light in conjunction with a ceiling fan may help sterilize the air and reduce risk (McDevitt, J., et al., 2008.) (An upper-room germicidal UV lights costs less than $1,000 USD.). New UV sterilization technology is still under review (Buonano, M., Welch, D. et al., 2020), but its efficacy is unproven, and can be cost-prohibitive, over $1,000 USD each with limited current supply (Milton, 2020).
Indoor airflow may become a vector of transmission (Lu, J., Gu, J., et al., 2020); therefore, engage your building manager/safety officer soon to discuss any necessary adjustments that can be made to the HVAC system (ASHRAE, 2020).
Personal Protective Measures
Social distance of 6 feet is still recommended by all researchers, though it might not be enough for symptomatic patients since coughing or sneezing can propel droplets much further (Bourouiba L., 2020).
Homemade masks are ineffective to protect against any viral air droplets (Kähler, C, and Hain, R., 2020). If you must meet, surgical masks for all is a must (Leung, N., Chu, D., et al., 2020).
Plans to Return and Safety Protocols
For a safe return, plan for the worst and hope for the best!
Creating or adopting any of the proposed safety protocols below will be productive, even when safe return is not immediately possible, or if there are still unknown in some parts of the protocol. It will help your organization take stocks of your rehearsal situation, evaluate the risks for singers, and provide necessary accommodations.
Be prepared that current science may not carry the news we wish to hear — Alberta Health, for example, currently “strongly recommended that singing not occur in person” (Statt, G., 2020). Do note that none of the documents state that singing is safe.
Center yourself; evaluate your assets and goals before proceeding (British Columbia Choral Federation, Choir Alberta, et al., 2020).
To draft a safety protocol, Dr. Claudia Spahn and Dr. Bernhard Richter have proposed a safety framework for the Freiburg Hochschule for Music, in a document prepared in May (Spahn, C., Richter, B., 2020). They laid out a three-stage exploratory model of safety protocol:
1. Intake control
symptom questionnaire
contact tracing
body temperature check
2. In-room parameters
make music outdoors OR
use a sufficiently large room (e.g. church, concert hall, other large room)
maintain good ventilation (natural ventilation recommended)
rehearse in short chunks (15 minutes) with pauses in between
3. Individual protective measures
masks
2 meters apart (6.5 feet)
To keep our singers safe through this pandemic, all steps should be well supported by research. Since this is a novel virus, more research is yet to come; our safety protocol should be open for modification as new studies become available.
Based in Eau Claire, Jerry Hui is the director of choral activities at the University of Wisconsin-Stout. He also directs Schola Cantorum of Eau Claire, the Chippewa Valley Festival Choir, and serves as the assistant conductor at the Madison Early Music Festival.
Endnotes (In order of Citation) and Article Summaries
Hamner, L, et al. (2020, May). High SARS-CoV-2 Attack Rate Following Exposure at a Choir Practice — Skagit County, Washington, March 2020. Morbidity and Mortality Weekly Report (MMWR), 69.
[Summary: Detail chronicle of the notorious choir rehearsal in which one index person got 86.7% of the choir sick. Non-singing group activities took place, but singing could have played a part.]
Bates, J.H., Potts, W.E., et al. (1965). Epidemiology of Primary Tuberculosis in an Industrial School. New England Journal of Medicine, 272:714-717.
[Summary: This describes a natural experiment on transmission of TB at an industrial school. Students who had choir with one index patient were much more likely to catch TB than others interacting with another index patient through attending classes.]
Loudon, R., and Roberts, R.M. (1968). Singing and the Dissemination of Tuberculosis. American Review of Respiratory Disease, 98(2), pp. 297–300.
[Summary: Singing generates fewer droplets than loud speaking, but the droplets’ infection potential is higher because of their average size. Droplets from singing also remain in the air for much longer than speaking and comparable to coughing. In other words: silent(er), but deadly.]
Asadi, S., Wexler, A. et al. (2020, Jan). Effect of voicing and articulation manner on aerosol particle emission during human speech. PLoS One. 15(1):e0227699.
[Summary: Plosives emit particles, but vowels are worse. The more vowels the worse. h/t to H. Nelson]
Asadi, S., Wexler, A. et al. (2019). Aerosol emission and superemission during human speech increase with voice loudness. Scientific Reports (9, article number 2348).
[Summary: The louder you are, the more aerosol you emit. Some people are super-emitters for unknown reasons.]
Patterson, B., Wood, R. (2019). Is cough really necessary for TB transmission?. Tuberculosis (Edinb). 2019 Jul; 117: 31–35.
[Summary: Coughing isn’t king: other respiratory activities can emit viral material just as effectively if the pathogen resides in upper airways — which SARS-CoV-2 does. h/t Chris Brown, MD, PhD Division of infectious diseases at Weill Cornell Medical College]
Qian, H., Miao, T., et al. (2020, April). Indoor transmission of SARS-CoV-2. [Preprint]
[Summary: Out of 318 outbreaks that took place in Wuhan during most of January 2020, only one outbreak took place outdoors involving two confirmed cases. Sharing indoor space is high risk for transmission.]
Stadnytskyi, V., Bax, C., et al. (2020, May). The airborne lifetime of small speech droplets and their potential importance in SARS-CoV-2 transmission. Proceedings of the National Academy of Sciences.
[Summary: Speech generates lots of air droplets, which may transmit respiratory illnesses. One minute of speech can generate at least a thousand droplets that can remain in the air for 8 minutes, if the room is not ventilated and the humidity is low. Fun fact: they did the experiment by having someone repeat the words “stay healthy” for 25s.]
Morawska, L., Cao, J. (2020, April). Airborne transmission of SARS-CoV-2: the world should face the reality. Environment International, 2020 Apr 10: 105730.
[Summary: Authors reiterate the high possibility of COVID-19 spreading by air, and the necessity of increased natural ventilation.]
McDevitt, J., et al. (2008, Sep). Inactivation of Poxviruses by Upper-Room UVC Light in a Simulated Hospital Room Environment. PLoS One, 3(9): e3186.
[Summary: Upper room UV light + ceiling fan achieves effective inactivation of poxvirus compared to just relying on HVAC.]
Buonano, M., Welch, D. et al. (2020, April 27). Far-UVC light efficiently and safely inactivates airborne human coronaviruses. [Preprint, under review as of 5/14/2020].
[Summary: Far-UVC light is UV at a different wavelength that is safe to human at closer distance, compared to the traditional germicidal UV. The experiment shows efficacy against some other strains of coronaviruses within just 20 seconds of exposure. CAVEATS: 1) the far-UVC intensity was bumped way up during the experiment; at a humanly acceptable intensity, 25 minutes of exposure is required (community discussion, 11 May 2020); 2) it has not been tested on the current SARS-CoV-2.]
Contributor, Milton, D. (2020, May 5). In What Do Science and Data Say About the Near-Term Future of Singing? [Panel discussion]. American Choral Directors Association, National Association of Teachers of Singing, and Chorus America.
Lu, J., Gu, J., et al. (2020, July).COVID-19 Outbreak Associated with Air Conditioning in Restaurant, Guangzhou, China, 2020. CDC Emerging Infectious Diseases, 26(7).
[Summary: Larger distance between people and better ventilation may be necessary.]
American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). (2020, April 14). ASHRAE Position Document on Infectious Aerosols.
[Summary: Humidity of 40-60% is bad news for virus, but make sure you talk to building managers and safety officers first before bringing your own humidifier because mold. (Note: ASHRAE does not make this an official recommendation.) (Note: Your building managers/safety officers may find actionable solutions in this document to adjust your building HVAC.)]
Bourouiba L. (2020, March). Turbulent Gas Clouds and Respiratory Pathogen Emissions: Potential Implications for Reducing Transmission of COVID-19. JAMA. 2020;323(18):1837–1838.
[Summary: Concerning coughers and sneezers, 6 feet is not enough for safety. PPE is absolutely necessary for those working with symptomatic patients. More studies are called for on the effect of surgical/N95 masks on sneeze/cough clouds. h/t Brian Teague, Biology, UW-Stout]
Kähler, C, and Hain, R. (2020, April). Flow analyses to validate SARS-COV-2 protective masks. Preprint.
[Summary: First mentioned and misread by a Zurich Katolisches Medienzentrum article, this research has nothing to do with singing being safe. Surgical masks reduce airflow velocity effectively when correctly worn. Household material is useless in filtering air droplets, EXCEPT vacuum bags.]
Leung, N., Chu, D., et al. (2020, April). Respiratory virus shedding in exhaled breath and efficacy of face masks. NatureMedicine, 26, pp.676–680.
[Summary: Symptomatic? Wear a surgical mask. CAVEATS: Cloth masks were not tested; current strain of coronavirus was not available for testing in 2013-2016.]
Statt, G. Guidelines for Choral Singing from Alberta Health. (2020, May 25). [Letter; Deputy Incident Commander of the Emergency Operations Centre and Assistant Deputy Minister – Pharmaceutical and Supplementary Benefits Division of Alberta Health, in response to a letter from Choir Alberta and Pro Coro Canada dated 11 May 2020].
British Columbia Choral Federation, Choir Alberta, et al. (2020, May 20). Planning for Your Choir In Uncertain Times — A Framework. [Archived copy; accessed via Dr. Tim Sharp]
[Summary: This is a guide for conductors to begin drafting strategies to return to rehearsals safely, and what rehearsals might look like.]
Spahn, C., Richter, B. (2020, May 19). Risikoeinschätzung einer Coronavirus-Infektion im Bereich Musik (Risk assessment of Coronavirus infection in the field of music; live link, archive). [Internal document, collaboration between Freiburg University Medical Center and Freiburg Hochschule for Music].
Additional Resources
Center for Disease Control and Prevention. (2020, May 7). Reopening Guidance for Cleaning and Disinfecting Public Spaces, Workplaces, Businesses, Schools, and Homes.
Europa Cantat. (2020). Covid-19 information for choral organisations, choirs and conductors: Information gathered by the European Choral Association - Europa Cantat, spring 2020. [Comprehensive resource on rehearsal safety, suggestion for protocols and curriculum.]
McBroom D. (2020, May 5). “List of articles mentioned”, supplement to Webinar 1. What Do Science and Data Say About the Near-Term Future of Singing?. [A collection of news articles and scientific researches compiled as a preparation for the webinar co-hosted by ACDA, the National Association of Teachers of Singing (NATS), Chorus America, Barbershop Harmony Society, and Performing Arts Medicine Association (PAMA).]
Nelson, H. (2020, April 29). Singing, the Church, and COVID-19: A Caution for Moving Forward in Our Current Pandemic. [Personal blog] [Heather Nelson is a Springfield, MO-based voice teacher. Her blog post curates a plethora of good news articles and scientific researches.
Acknowledgments
I would like to thank Brian Teague (Biology, University of Wisconsin-Stout) and Chris Brown (MD, PhD Division of infectious diseases at Weill Cornell Medical College) for their input in preparing this document and in collecting additional studies.