Coronavirus destroyed the choir. But it didn’t spread any further.

It was a cold night at Mount Vernon, Washington, March 10. As with most Tuesday nights, a group of singers gathered in church to practice chorus.

The complete choir consists of 122 singers, but only 61 that night, fighting cold-like symptoms for several days.

The person later tested positive for coronavirus, and six members of the choir had a fever within two days of treatment. Eventually, 53 members of the choir fell ill with Covid-19, a disease caused by the virus, and two died.

First reported event Los Angeles Times of March, He showed how coronaviruses are contagious and dangerous, especially among the elderly. The median age of those who participated in the evening practice was 69.

Subsequent studies indicated that swift action by members of the choir, including voluntary isolation, along with contact tracing by the Skagit County Department of Health could contain the spread and be a much larger outbreak in the community. It shows what helps prevent one hour north of Seattle by car.

The virus spread quickly and thoroughly within the choir, but did not lead to a significant increase in infection rates throughout the community.

“If they hadn’t started their own quarantine and quarantine before we got involved, I can imagine a situation where all three of them were infected by three different people,” Skagit County Health. Dr. Howard Reybrand, who is in charge, said. “Based on this one episode, I think there was a big change in the virus curve.”

Reports like these are outbreaking for a large number of people as communities around the world begin to look at ways to ease restrictions on movement and gatherings and reopen businesses and places of worship. This is especially true when activities such as singing can be contagious.

Dr. Reybrand and Skagit County epidemic and epidemiology supervisor Dr. Lee Hamner investigated the occurrence of chorus and were the authors of a report released Tuesday by the Centers for Disease Control and Prevention.

They classified choir practice as point-source exposure, and said such events were not so clearly separated, providing a useful study of how the virus spreads.

“It’s rare to have a group with a single common exposure,” Dr. Hamner said. “Here we have defined groups and they all experienced similar exposures over similar times, so that kind of event allows us to understand the transmission a bit better.”

It is likely that the act of singing is so fertile that choir practice has become contagious. People projecting loud voices tend to emit small droplets called aerosols that can carry the virus. This is a phenomenon known to anyone who sits near the stage when performing a drama or a musical performance.

“By projecting your voice, you can project more viruses,” said Dr. Reybrand. “So this seems to be a pretty good indication that we shouldn’t go back to a closed space, a large group singing in a church. It’s a situation similar to this. “

Some people in the Skagit County Choir may have been what the report calls superemitters — people emit more particles than others during a speech.

According to the Washington Department of Public Health, the total number of cases in Skagit County was 406 as of Tuesday afternoon.

Pia MacDonald, an infectious disease epidemiologist at RTI International, did not participate in the study, but it is worth noting that the outbreak of the choir did not lead to infection throughout the community. A few days after practice.

“There are still days where people might have been walking in close contact with other people,” she said.

The practice took place from 6:30 pm to 9 pm, with many of the choir members sitting in spacious rooms with designated seats. Sheets are grouped together 6-10 inches apart and are C.D.C. Was much closer than the recommended minimum of 6 feet recommended by. During a pandemic.

Many were sitting next to vacant seats, as only about half of the choir members are there. But later they split into another group and served cookies and oranges during a break in the back of the room.

At the end of practice, some members helped clear the chair, and this contact with the surface may also have contributed to the infection.

A few weeks ago, Washington reported the first case of coronavirus. This is related to travelers from Wuhan, China, where the outbreak began, but recognition of coronaviruses in Washington and many parts of the United States was still in its infancy on March 10.

On March 15, Dr. Hamner and Dr. Reybrand said choir directors sent emails to all of the choirs to report that six were ill. From that point on, they said members of the choir were keen to remain isolated.

Three days later, they began an investigation and began working with the Skagit County Department of Health, which began tracking contacts. Doctors said the choir members were very helpful, not only maintaining self-quarantine, but also approaching providing useful information to help with the investigation.

“They were the ideal group to work with to investigate the disease,” said Hamner. “I’ve been investigating illness for five years and it was a really great relationship.”