Your questions, answered
“How great is the risk of transmission in churches, which are enclosed spaces, when pastors, choirs members and speakers disregard safety guidelines and take off their masks when speaking and singing?” — Robert in Las Vegas
According to health experts, the scenario Robert describes is among the highest risk for transmission of the coronavirus.
Earlier this month, the Centers for Disease Control and Prevention updated its website to say that airborne transmission is possible. It was something health experts assumed was happening all along, but they didn't have a lot of hard evidence to support creating guidelines about the risk.
Airborne spread goes beyond person-to-person transmission. The CDC says the virus can linger in the air for hours. The six-foot social distancing rule doesn't help in this case. It's particularly concerning in enclosed spaces with poor ventilation (such as churches). It's even more concerning when people aren't wearing masks while they are speaking, shouting, or in this case, singing.
A little more about risk, which we touched on briefly in yesterday's reader question: There's no such thing as a “no risk” gathering. Risk comes on a scale from low to high, and some gatherings are worse than others. We find this chart, developed by a British research team, particularly helpful to assess the risk.
Robert's scenario, in which people are gathered and speaking and/or singing without masks, falls in the lower right corner of that chart. The more crowded those gatherings are, and the longer they last, the riskier they become.
We've seen real-world evidence that church gatherings are a potential source for infections. Contact tracing helped officials in South Korea determine that one church accounted for more than 5,000 confirmed coronavirus cases over approximately a month – more than half of the country's total caseload at the time. It wasn't isolated to the church itself, of course. The people who contracted the virus there went out and spread it to others.
Outbreaks have been tied to churches in the United States, too. Early in the pandemic, the L.A. Times reported dozens of choir members who met for practice at a church in Washington state were diagnosed with covid-19, and at least two died.