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COVID-19 NFHS Study Update

As of today (April 19th, 2021), we have some important updates on the current state of the COVID-19 pandemic and congregational singing. Many of you will be aware that a large number of public education organizations have been sponsoring a scientific study out of the University of Colorado Boulder and the University of Maryland. That study has just released another update on their findings and updated their recommendations. Below is a link to the full paper, important excerpts that pertain to congregational singing, and my personal summary of the new information.


Full Paper Link

NFHS Scientific Study Prepress Paper (40+ Pages) (April 15th)

Important Excerpts

  • Using masks greatly reduced the aerosol concentration measured in front of the source. Plumes from talking, singing, and performing musical instruments were highly three dimensional and vary considerably in time and space. The plumes decayed rapidly and are highly unsteady, which lead to large variations in our plume-level measurements. In addition, our flow characterization data show that when masks were used, plumes were shorter and plume velocities decreased, which decreased the trajectory of highly concentrated jets of aerosol.
  • CFD modeling showed differences between outdoor and indoor environments of singing and playing the clarinet without masks. In an outdoor environment, ambient wind breaks the musician’s thermal plume and expelled airflow and accelerates the dilution of aerosol. In an indoor environment, the musician’s thermal plume and expelled airflow contribute to the spread of aerosol due to space confinement. In addition, the indoor walls force the formation of smaller eddies, and the consequent distribution of the particles. To minimize infection risk to musicians and audiences via aerosol, this study showed lowest risk with an exposure duration less than 30 minutes for indoor singing and clarinet playing, and an exposure duration less than 60 minutes for outdoor performance.
  • Face shields are only effective at close range to stop large droplets (such as the visible droplets from a cough or sneeze) and do not prevent aerosol from being emitted or inhaled. Much of the respiratory particles emitted are small in diameter and follow streamlines around face shields.
  • Performers should follow social distancing protocols as recommended by the CDC for music activities. Aerosol concentrations are highest closest to the source, both inside and outside, and decrease with distance.
  • If indoor spaces are used, we recommend having at least three air changes per hour in the rehearsal room and limiting rehearsal time to 30 minutes at a time before leaving the room for at least one air change. For a room that has three air changes per hour, one air change is 20 minutes.


My Recommendations/Summary

  • This new information reinforces the importance of proper mask-wearing.
  • In general, outdoor events are significantly safer than indoor events.
  • This new information reinforces the difference been shields and masks. Shields do not protect the wearer or other from aerosol transmission.
  • Air circulation, distribution, and “air changes” are key components to virus spread through aerosols. However, air circulation and distribution are unique to each building and room and highly effects how much and where aerosols may spread. Unless you have an airflow expert analyze your rooms, this is a big variable that makes comparing situations between churches nearly impossible.
  • The authors of this study are not recommending any distancing beyond what the CDC recommends. The current CDC recommendations for communities of faith (found here) are the same as their general social distancing recommendations: 6 feet.
  • These recommendations remain true for fully vaccinated individuals as per the CDC guidelines for fully vaccinated people here.


For more updates and resources on COVID-19 and congregational singing, please go to:

This update is written by Center Director Brian Hehn and should be used only as general advice in consultation with other trusted sources. This is his personal summary of the data presented and should not be considered scientific fact nor medical advice.


There are currently research teams across the world working on identifying how COVID-19 spreads and how to best protect the population from contracting the virus. Two ongoing studies are particularly focusing on music-making, which is what we will reference in this summary article. Before continuing, a few important considerations:

  • The author of this article is a professional musician, not a scientist. However, all information posted here has been carefully researched to the best of his ability.
  • Because of the nature this virus and of risk-assessment in general, every situation is unique and you and your team of decision-makers must try to make the best decision for your community. What is the best decision for a group in Atlanta may not be the best decision for someone in Dallas. Think for yourselves and do your own research.



There have been two recent studies specific to music-making and COVID-19 that are being posted on social media, advertised by sponsoring organizations, and being mentioned by media outlets. One is based out of Ludwig-Maximilians-University of Munich and the other based out of the University of Colorado. Below are summaries of those study results and the highlights that stood out to me. Finally, we’ll offer recommendations for moving forward as it concerns congregational singing.


Ludwig-Maximilians-University of Munich Study

Article Link*,aerosolebeimsingen100.html

*The article and the quotes from it found below were originally in German and translated to English via the automatic Google Translate function via the Chrome browser.

Lead Researcher – Prof. Matthias Echternach of Ludwig-Maximilians-University of Munich

Important Quotes/Hightlights:

  • “As far as the widths forward [of the aerosols], it was the case that the sung text had the largest width. Interestingly, here it is so that loud and quiet didn’t make that big a difference, loud only went on marginally – and that makes sense. Because singers still have to convey the text very well when they sing softly. That means that they showed a lot of text accuracy and the width of the radiation to the front probably has a lot to do with the consonant abundance.”
  • “Here we had an average value of around one meter. But you have to say in the risk assessment that there were also singers who got over it up to a meter and a half. This means that the classic distance, as we know it from everyday life, is too small towards the front when singing. This is the first main finding. The second is the spread to the side. Here we were able to demonstrate significantly smaller distances.”
  • “What we have examined needs to be narrowed down briefly. We have not investigated how much aerosol is formed or how it can accumulate in the room over the long term, other working groups do that. Instead, we examined the process of how the aerosol behaves when it is ejected from the mouth into the room. This means that the advice we give can only relate to this impulse. If we think about distance rules now, we can say: two to two and a half meters to the front should very likely be sufficient, to the side one and a half meters should be enough – provided the aerosols are repeatedly removed! And this removal is not a problem in the fresh air. But it could be a problem indoors. If you could get a continuous ventilation, then you could probably orientate yourself on the normal rehearsal times. If this cannot be guaranteed, I have to have regular intermittent ventilation, preferably after ten minutes.”


Our Summary

  • This study is not peer-reviewed yet nor has its results been duplicated by other studies. It, therefore, cannot be deemed as scientifically reliable. It can inform our decision-making but should not be upheld as scientifically “true” until it meets more rigorous standards.
  • There were singers whose projection of droplets exceeded 6 feet, which is the current standard recommendations for social distancing. This study is recommending 12 feet.
  • Singing loudly or softly didn’t make a significant difference in droplet projection
  • They did not study aerosol dispersion or used masked/unmasked variants in this study.



Study Link –

Lead Researchers – Dr. Shelly Miller of the University of Colorado and Dr. Jelena Srebric of the University of Maryland

Important Quotes/Highlights:

  • “These preliminary results are from our few weeks of exploratory testing. They will be further defined as the study continues. We are providing these preliminary results to assist in the safe return to classrooms. (Normally we do not release data until they have been quality assessed and peer reviewed).”
  • “This study did not use a live virus or infected participants and therefore cannot be used to determine specific infection rates.”
  • Mask Graphic from study PDF:



  • After talking about efficiency/effectiveness of masks in keeping people safe, they say:
  • “These numerical findings need to be compared to actual experimental data as numerical simulations cannot replace experiments when studying new transport phenomena, especially the ones that threaten human life.”
  • “Performing arts activities have been found to create aerosol that is less than coughing, but more than talking. The following considerations are effective for music, speech, theatre and debate activities.”
  • Airflow matters significantly in aerosol build-up


Our Summary

  • This study is not complete.
  • This study is not peer-reviewed yet nor has its results been duplicated by other studies. It, therefore, cannot be deemed as scientifically reliable. It can inform our decision-making but should not be upheld as scientifically “true” until it meets more rigorous standards.
  • Singing and playing wind instruments is seems to be riskier than speech, however it is not as risky as coughing.
  • Masks make a difference, but masks must be fitted and worn properly.



As of today, we continue to err on the side of caution, not because we are fearful but because we are faithful. We believe that the health and lives of congregations across the U.S. are more important than any single act of music-making. God calls us to love and care for our neighbors. There will be a time we can sing together in our churches again, but the two studies referenced above do not provide scientific evidence that it is safe for a congregation to do so right now. They should give us hope, but they should not give us permission. The scientists leading the studies have said as much. So please reference these studies and continue to look for updates. But do not be fooled or allow yourselves to read those studies as scientific proof that there are risk-free ways of singing together.


For more resources and updates concerning COVID-19 and Singing, please go to:


Blogger Brian Hehn is the Director of

The Center for Congregational Song.