Choirs are a secret lifeblood of our country. It’s unclear when and how we’ll ever sing together again.

Every five years in July, more than 1,000 choirs gather to perform together in Tallinn, the impossibly pretty seaside capital of Estonia. As many as 35,000 choristers (oldest: 90; youngest: five) process through medieval cobblestone streets to the festival grounds, where they join in song with an audience of 85,000. The effect is what an official video calls “not merely singing… but breathing together.” From the moment I learned about this event from a friend who attended last year, it became a dream of mine to experience it.

Until, of course, it became a nightmare. It’s not just that a gathering of 120,000 people would be dangerous during a global pandemic. It’s that singing itself might be particularly dangerous. After a single (now notorious) rehearsal of the Skagit Valley Chorale in Mount Vernon, Washington, in early March, 45 of the 60 attendees fell ill with symptoms of Covid-19 and at least two have died. As Vanity Fair reports, scientists have traced other outbreaks to a funeral, church service, and rowdy bar, all involving enthusiastic group singing. Japanese scientists have reported outbreaks possibly tied to karaoke bars, says William Ristenpart, PhD, a professor of chemical engineering at the University of California, Davis.

A handful of anecdotes isn’t evidence, epidemiologically speaking. And the question of whether Covid-19 is a so-called airborne disease remains hotly contested. Ristenpart is among those who believe it may be: He’s the senior author of a recent editorial in Aerosol Science and Technology hypothesizing that simply having a face-to-face conversation with an asymptomatic infected person might be enough to transmit Covid-19.

Here’s the evidence: The CDC tells us that the coronavirus that causes Covid-19 chiefly spreads person-to-person via respiratory droplets that we emit when we sneeze or cough. These droplets are large enough (about 50 microns) that you can see them. But we also emit much tinier aerosol particles (as small as one micron) whenever we breathe, talk, or sing.

The louder you are, the more particles you emit and the greater risk you would infect the people near you.

A few of us even appear to be “superemitters,” spreading an order of magnitude more of these fine aerosol particles for an as yet unknown physiological reason, the UC Davis researchers found in a 2019 study in Nature’s Scientific Reports. Because the particles are invisible to the naked eye, there is no way to know whether the singer sitting next to you at rehearsal could be a superemitter. (They are not to be confused with superspitters, who are easy to spot — looking at you, Ben Platt.)

Not only can these tiny particles carry respiratory disease like the coronavirus, but they may also be more infectious than larger droplets, the study proposed. Because aerosols are so light, they may hang in the air for hours. They may reach deeper into the lungs than droplets do. Most important, there are more of them: Saying “aah” for 30 seconds produces twice as many particles as coughing nonstop for the same amount of time, according to a study in the Journal of Aerosol Science. And singing, according to research done on the spread of tuberculosis, may produce six times the rate of small airborne droplets as speaking does.

In fact, almost everything about singing seems to create more (potentially virus-spreading) aerosols. Ristenpart explains the mechanism: When you exhale, mucosal fluid forms a film deep in your contracting lungs. When you inhale and your lung walls expand, the film bursts, creating aerosol particles that are then breathed out into the world. “The rate at which you inhale or exhale affects the number of particles you emit,” he says. Deep, slow breathing followed by a fast exhale would produce the fewest particles. The greatest number would come from quick inhalation (causing a more violent film burst) followed by slow and prolonged exhaling. “That’s kind of a description of singing,” Ristenpart says.

A similar film-burst effect happens in the larynx as your vocal cords expand and contract — and your cords vibrate more when you sing than when you speak. Your volume also matters: The louder you are, the more particles you emit and the greater risk you would infect the people near you. For example, the UC Davis study suggested, “airborne infectious disease might spread more efficiently in a school cafeteria than a library, or in a noisy hospital waiting room than a quiet ward.”

As for a choral concert? “Would singing cause a large number of expiratory particles to be emitted? I would say absolutely,” Ristenpart says. Whether those aerosols actually transmit disease depends on additional factors — like airflow, to name a big one. Still, says Ristenpart, “if that choir in Washington had sat for two hours of meditation instead of singing, the transmission would almost certainly have been much lower.” There is abundant evidence to suggest that Covid-19 is spread via aerosols, he adds, “but a lot of people are very resistant to that idea, because the potential implications are a bit terrifying.”

For those of us who sing in choirs, the idea is almost too heartbreaking to bear. Suddenly one of the healthiest things I do for myself every week has become an agent of plague.

A couple years ago, I was feeling untethered. I had a job I loved at a company that was circling the drain. The daily headlines offered a crushing stream of cruelty, dishonesty, and science denial. Everywhere were reminders to practice “self-care”: Meditate, bathe, stretch, pamper, unplug. All of which felt to me like retreat, when what I wanted was connection. So, I joined a choir.

I hadn’t sung with a group since my college a cappella days. But it came back like a bike ride. Every Wednesday night, I’d sit with about 50 other New Yorkers in a choral room on loan from a private school on the Upper West Side. Measure by measure, we’d work through arrangements of Johannes Brahms, Aaron Copland, Cole Porter.

To me, this is meditation. When I am simultaneously sight-reading six-part harmony, counting out the time signature, and sounding my way phonetically through words in Hebrew or Latin, every cell in my brain is necessary to the task. There’s no room left for whatever thoughts were nagging me when I walked in the door. I liked the feeling so much that soon I was volunteering for my church’s choir as well, waking up early on Sundays to make pancakes for my daughters and slip out to rehearse before services.

I told people about my new hobby a bit sheepishly. Joining a choral society is not cool. There’s not much glory in it… and that’s kind of the point. Choral singing is an old-school act of community in an Instagram world. Compared to the general public, the 54 million Americans who sing in choirs are more likely to give money to charity, volunteer, run for office, and check the newspaper daily, according to a 2019 study of 5,400 singers by the nonprofit association Chorus America. They are more likely to go to museums, spend time in nature, and exercise. Ninety percent of them vote.

Singing in a chorus seems to have a significant impact on mental health. In the Chorus America survey, singers reported that the activity has increased their optimism, resilience, and mindfulness. Belonging to more ensembles, rehearsing more frequently, and having been singing longer all increase the benefits. Older choristers report fewer cognitive issues and much better quality of life than the general public. It’s not just that happier people are signing up: When researchers at UC San Francisco studied the health effects of having older adults join community choirs, they found that taking up the hobby significantly reduced loneliness and increased interest in life — a potentially important finding given the rates of depression in older Americans. (The study did not find improved cognitive or physical function, however.)

Handel wrote his ‘Coronation Anthems’ to be performed for King George II in Westminster Abbey, not into a laptop in my study with my mic on mute.

I fear for the mental health effects on members who have lost their support system. “We find ourselves in an environment that is the antithesis of our mission, which is about connection, social engagement, and the nuance of blending voices,” says Catherine Dehoney, president and CEO of Chorus America. “The social, emotional, and physical benefits we reap from singing together are not able to be replicated individually in the same way.”

Pre-pandemic, my fellow singers sat shoulder to shoulder, leaning in to compare notations, borrow a pencil, or whisper a question in our neighbor’s ear. On breaks, we shared hugs, stories, and grapes straight off the bunch. Now, two members of my church choir are in literal isolation, on lockdown at an upscale retirement community that’s seen 40 employees and 26 residents infected and 12 people die.

Under what circumstances, I asked Ristenpart, might it be safe for singers to reconvene?

“Over Zoom,” he replied.

As the proverb has it, those who wish to sing will always find a song. Social distancing has inspired some moving virtual performances (watch a few of them here). My college group, the UNC Loreleis, sent out a call to see how many alums would want to make a joint video and received positively Estonian levels of participation: More than 100 women have signed up. Because of the lag time involved in videoconferencing, singers can’t sync up live, so each will record her own part and be blended into a whole through the magic of editing.

Still, as Dehoney admits, “singing by yourself just isn’t the same thing. The tech doesn’t exist yet so that people can actually sing together virtually. We are being flooded with requests for best practices of how we can come back together safely.”

What that looks like is unclear. No masks are currently safe for singing, Lucinda Halstead, MD, an otolaryngologist at the Medical University of South Carolina, said in a recent webinar, and effective screening would involve the daunting prospect of giving every member PCR tests to detect infection 24 hours before rehearsal. Eventually, choruses might meet in smaller groups, install UV-light air-disinfection systems, or hold rehearsals outside, where a gentle breeze may help waft away infectious aerosols. Social distancing remains key, though if Covid-19 is indeed airborne, we may need to revisit our idea of a safe distance. “The risk is never going to be zero,” said Halstead, who is also president-elect of the Performing Arts Medical Association.

Meanwhile, we keep singing because we can’t not. Last Wednesday night, I logged on for a digital rehearsal of my Upper West Side choral society. It was lovely to be together and see that everyone was safe. It was not, to put it charitably, meditation. Handel wrote his Coronation Anthems to be performed for King George II in Westminster Abbey, not into a laptop in my study with my mic on mute. (If a soprano hits a high A and no one is there to compliment her, did she really make a sound?) Our music director was heroic, but without fellow singers, it was harder to follow the music and stay in tune. I felt self-conscious — the enemy of art.

We closed with “Bridge Over Troubled Water.” I first performed this song with my high school chorus, and teenage me found it insufferably cheesy. Maybe I hadn’t felt weary or small enough at that point to appreciate it. On this night, listening to the piano accompaniment and watching nearly 30 other singers soundlessly mouth the words, I didn’t roll my eyes. I sighed for what we have lost, what we still have, and the agonizing mystery of what comes next. And then I sang out, like an idiot, alone in the light of the glowing screen.