Choirs may be super spreaders – NRC

At the beginning of March, just before the lockdown, the Amsterdam Mixed Choir sang Bach’s Johannes Passion in the Concertgebouw. It turned out that the coronavirus had already infected a few members. Of the 130 members of the amateur choir, 102 fell ill because of the rehearsals and this performance, including the conductor and accompanying musicians, the newspaper reported. Faithful this weekend. A choir member and three partners of choir members did not survive.

Something similar happened in the US: One person with the virus went to a 2.5-hour rehearsal with 61 choir members in Skagit County, Washington. 52 people subsequently fell ill – 32 of them had confirmed Covid-19, the rest probably also. Three were hospitalized, two died, the US Center for Disease Control reports this week.

The events show that singing in a choir can lead to ‘super spread’ of the virus, just like celebrating carnival, or hopping in an Austrian après ski bar.

Also read: The unknown facts about corona infectivity

The messages cause a lot of unrest in choirs, says Daphne Wassink of KorenNetwork Netherlands. “Many of our members are eager to sing again when 30 people are allowed to reunite on June 1. But others are just hesitant about it. ” Understandable, she thinks. The vast majority of the more than 1.5 million singers in amateur choirs in the Netherlands are over 60 years old, so many people are in the risk group.

The government gives conflicting signals as to whether or not singing together is possible. Last week Prime Minister Mark Rutte indicated in the press conference that singing in groups is really not yet possible. But some choir members say from RIVM that cultural institutions of up to 30 people can start again.

“Be cautious”

“Whether there is an additional risk of infection with the coronavirus when singing in a choir is not yet known,” said RIVM spokesperson Loes Hartman. The institute starts a literature search to list the knowledge. She cannot yet say whether singing with a mask on and with a 1.5 meter distance between the singers is safe. “Be careful,” she advised.

The question whether singing people can spread the virus is related to the question whether the coronavirus can only be transmitted through relatively larger cough, sneeze and speech droplets, which fall to the ground within a meter and a half, or also through finer breath droplets, aerosols, which float for hours. Virologists are not yet sure about that. It appears that the virus may also be in the fine droplets, but the dose of virus in it is usually not enough to infect someone unless there are a lot of them, such as when ventilating a corona patient in intensive care. But in enclosed spaces where many people sing – or shout or pant – together, such aerosol droplets may linger in higher concentrations.

Also read: Can you get corona from tiny breath droplets?

“Singing certainly releases large drops, just like screaming and talking,” says Nijmegen professor of infection prevention Andreas Voss. “Not as much as with coughing or sneezing, but singing continues longer. This increases the likelihood that someone who is in the same poorly ventilated area as a singing corona patient for a long time will be exposed to a dose of virus that can lead to infection. ”

Ventilate well

Voss advises not to work with thirty people yet. Singing with a small group does not seem a problem, under certain conditions. A group of four now sings in his own church. “With the knowledge we have now, it would be possible with small numbers of people, who are at least 1.5 meters apart. In addition, members must be asked well in advance about symptoms: whoever has mild complaints, stays at home. Just like everyone else in society. ” The rehearsal space also determines the decision. “There is more risk of infection in a small, poorly ventilated room than in a large, well-ventilated hall. He recommends taking a regular break and ventilating well.

He sees little danger of contamination by the fine droplets. “We still assume that the transfer takes place mainly through the larger splashes and drops. That doesn’t mean it can’t be done the other way, but it is less plausible. ”

There is also unrest among professional choristers, says Willemijn Mooij, director of the Netherlands Bach Society, a professional ensemble. “They would like to start again.” Together with TU Delft, the Dutch orchestral and choirs organizations started research projects into the spread of the coronavirus by singers and musicians with wind instruments, and into ways to protect them against it.

Zeeland traditional costume caps

TU Delft organized a so-called yesterday hackaton with almost fifty industrial design students. All day long they came up with solutions in groups that could prevent the spread of the virus to choristers. At the end of the day, they presented the ideas to each other and to a jury of musicians via Zoom. Advanced face masks and main screens such as Zeeland traditional hoods came along, but also individual single shower tents that are also used during camping, and plexiglass boxes stacked on stage. “A working group of five students will continue with the chosen ideas,” says organizer Sicco Santema, professor of Network Design & Innovation. “They will test whether the solutions conceived can indeed prevent contamination and, for example, do not affect the acoustic quality.”