In early July violinist Daniel Froschauer arrived in Salzburg with the Vienna Philharmonic, of which he is also the Chairman. The orchestra was to perform at the Salzburg Festival the entire month of August, under strict regulations to ensure that the musicians and their audience are at minimal risk of catching or spreading the SARS-CoV-2 coronavirus.
“If the Salzburg Festival is successful, our season can start in September,” Froschauer said, “Up to a point where we might have to stop again, but at least we could start.”
The Vienna Philharmonic was one of the first professional orchestras to return to rehearsals and performances since the start of the COVID-19 pandemic, but it wouldn’t have been possible if they hadn’t carried out their own small research study into the way droplets disperse on stage while musicians play.
This spring, it became clear that stage performances and rehearsals could pose a significant risk for infection with the SARS-CoV-2 virus. The case of a choir rehearsal in Washington state back in March was a wake-up call for many musical ensembles. The choir thought they were prepared. They didn’t hug, they stood six feet apart throughout their two-and-a-half-hour rehearsal, and they didn’t share food during the break. Despite their precautions, 53 members of the 61-piece choir caught Covid-19, and two died.
If such a spread could happen at a choir rehearsal, then an orchestra or band rehearsal – particularly one with wind and brass instruments – might pose a similar risk. The virus can be passed on through tiny airborne droplets called aerosols from an infected individual’s mouth or nose. However, without knowing exactly how these aerosols move through the air from person to person, the risk to performers and their audiences wasn’t clear.
Until a few months ago, we knew very little about how wind instruments spread droplets. It was only since the COVID-19 pandemic that orchestras and other ensembles suddenly needed to understand exactly how singing or playing instruments could spread the virus so that they could mitigate the risk. Professional orchestras wanted to go back to work. Amateur groups and school ensembles wanted to know how they could safely return to rehearsals. If there was no existing research, they were going to have to make sure that the research got done – and fast.
The Vienna Philharmonic enlisted the help of physician Fritz Sterz. Initially, Sterz and Froschauer hoped that the Vienna Philharmonic members were immune already. The orchestra had passed through Wuhan on a tour of Asia in late 2019, perhaps already encountering the virus there. But this didn’t seem to be the case: Only one member of the orchestra tested positive in an antibody test.
The next step was to figure out how rehearsals were putting them at risk, by determining how aerosols were formed around their instruments. Although Sterz isn’t an expert in aerosols, he understood their relevance. “I work in the intensive care unit of the emergency department of the Vienna General Hospital,” says Sterz. “There I often deal with the problem of aerosols spreading around the room.” The issue was the same whether it’s the emergency room or the stage: how could you measure where these aerosols are going?
Sterz and the orchestra found a creative way to visualise the aerosols’ movement. Each musician was placed in front of a dark background and wore a device up their nose to produce aerosols as they breathed. While playing their instruments, the musicians dispersed the droplets, and a photographer captured images of the cloud of aerosols surrounding each musician.
By measuring the dispersal of the droplets for each instrument, Sterz was able to get a sense of which musicians created the largest air flow around them. Unsurprisingly, it was the wind musicians.
“I’m not an aerosol researcher,” Sterz emphasizes. “I don’t want to compete with aerosol researchers because I don’t have the experience or the knowledge. I just wanted to take pictures and that’s how it worked.”
In lieu of the traditional peer review process that follows most scientific studies, the Vienna Philharmonic worked with a notary to verify that they carried out the procedures as they said they did, and that the results were what they measured. It wasn’t the way research is usually done, but it was enough to convince the Austrian government.
The New Normal
In May, Froschauer got a call from the Austrian Prime Minister. The Vienna Philharmonic was allowed to rehearse, record and perform again, albeit under very strict conditions. To make it work, the musicians are regularly tested, stay a safe distance apart on stage, wear masks when they have to be near each other in the hallways, and limit the size of the audience.
Only a hundred people were allowed in the audience at their first performance in Vienna in June. It wasn’t even worth selling tickets for, but the musicians were thrilled to be back. “It was a sad time without music and I can’t tell you how incredibly happy I am that we can perform,” says Froschauer. “My life is going on stage where I see the conductor and the audience and everybody is experiencing a great performance together.”
Researching the Spread of Aerosols
Meanwhile, other orchestras and music organisations have also taken the initiative to research how they could return to performing. Over the last few months, several studies have released preliminary results. Research projects working with Brass Bands England and with the Minnesota Orchestra have both recently uploaded preprints of their manuscripts to MedXRiv ahead of peer review and publication, and in May, the German Bamberg Symphony Orchestra was one of the first orchestras in the world to measure the spread of aerosols by their instruments.
In the United States, the National Federation of State High School Associations and the College Band Directors National Association funded the Performing Arts Aerosol Study to determine the best recommendations for school bands, orchestras and other performing arts groups returning to practice this fall term.
Shelly Miller, professor of environmental engineering at the University of Colorado Boulder, is one of the lead researchers on the study. She explains that in their preliminary studies they coupled the study of airflow with the detection of aerosol particles generated by different instruments.
“We initially wanted to understand where all the air flow was,” Miller explains. In other words, was it coming from the keyholes, the mouthpiece, or the bell of the wind instrument? “Once we knew what the flow looked like, we probed those flows to measure the particles in the flow.”
These experiments were different from what the Vienna study did. Sterz’s experiment visualised flow of aerosols generated from the nasal device but didn’t detect the individual aerosol particles. Despite the different methods, both studies found that wind and brass players (and singers) were more likely to spread aerosols than other musicians.
From the preliminary results, the Performing Arts Aerosol Study concluded that certain safety precautions needed to be put in place before bands and school orchestras could return to rehearsals.
It’s worth noting here that these various studies into the spread of aerosols between musicians nicely illustrate how the pandemic has changed the pace of scientific research. Normally, research is slow and the process of verifying, publishing and reviewing the work can be slower than the studies itself. But everything was different this summer. Music groups needed advice about returning to rehearsals and pushed for the research to be carried out, soon. It’s not normal for researchers to be asked to give advice based solely on preliminary data.
“It’s really intense,” says Miller, “because we would love to be helping and yet we don’t want to give bad guidance either. So our take is to be as conservative as possible, while still being helpful.”
Hygiene & Prevention
Formal peer review and publication will follow later – for now, it was more important to provide orchestras with useful advice, and that advice depends not only on the science, but also on the individual countries and music organisations.
Fritz Sterz’s top tip for keeping orchestras safe is to test players regularly for the SARS-CoV-2 virus. He says it even makes musicians play better, because a collective negative test result makes everyone relax more, knowing that the people next to them aren’t carrying the virus. Now the Vienna Philharmonic tests its players regularly and continued to do so while they were at the Salzburg Festival. Over Skype from Salzburg, Froschauer showed me the red lanyard the musicians had to wear to show that they had taken a Covid-19 test that day.
But for most smaller orchestras, including amateur groups and school ensembles, regular testing isn’t feasible or affordable.
“Testing and tracing is great,” says Miller, “but unfortunately, we don’t have enough testing capacity for the general population here in the US, so we needed to come up with recommendations on what to do.”
The advice from Miller and the other experts involved in the Performing Arts Aerosol Study includes using bell covers for instruments, play outdoors where possible, or have short socially distanced 30-minute rehearsals in a well-ventilated room with filtered air and enough time between groups to completely refresh the air.
It may mean shorter rehearsals and smaller groups, but for many ensembles, implementing the advice from these preliminary studies is currently the best option to keep musicians safe while still being able to play together.
“We’re trying to make environments safer,” says Miller. “You can’t completely reduce risk, but we are trying to make them safer.”
A Safe Outcome
In the end, the Salzburg Festival experiment was a resounding success: Among the staff, only one test in early July came back positive, and “because of the quick reaction of all those involved,” the Festival reported, “no further employees were infected.”
Among the more than 70,000 visitors, “not a single positive case has been reported to the authorities.”
Whether all the safety precautions will be enough to see musicians through a complete fall term of rehearsals is still up in the air, both in the US and in Austria. “I am a little bit worried because the numbers are going up and it’s very challenging to make plans right now,” Froschauer says about the Vienna Philharmonic’s upcoming season. He’s trying to stay positive, but he’s realistic about it. “If it doesn’t happen, I’m not going to be disappointed.”
A version of this article was first published on forbes.com. It appears here by permission of the author.