A choir of about 100 performers sang at a megachurch campaign event featuring Vice President Mike Pence on Sunday. They did not wear masks while they sang.

Many epidemiologists and singing experts currently fear that singers may be super-spreaders of COVID-19, due to aerosolization of the virus. Singing involves much more forceful and deep breathing than simple talking.

The choir singers were performing at the Celebrate Freedom Rally, which took place at Dallas’ First Baptist Church, which was billed as an event “to celebrate our freedom as Americans and our freedom in Christ with you through worship.” According to CNN, about 2,200 people attended the rally at the Texas megachurch, which can hold about 3,000 people. The singers reportedly had face coverings on between their selections.

Last Thursday, Texas Gov. Greg Abbott announced a “pause” on his state’s re-opening, after saying that Texas is facing a “massive outbreak” of the coronavirus.

All attendees at the First Baptist event went through temperature screenings before entering the megachurch, which boasts a membership of 13,000, and the church “strongly encouraged” those at the rally to use masks and observe social distancing. It’s unclear whether all performers and speakers were subjected to similar measures. Pence wore a mask himself except when he spoke.

On May 15, the CDC published a report on a two-and-a-half hour indoor choir practice in Skagit County, Wash. that took place in early March and was attended by 61 people. Afterwards, 85% of those singers apparently contracted the COVID-19 virus, with 32 confirmed and 20 probable COVID-19 cases. Three of the singers were hospitalized, and two died.

That month, the CDC posted guidance regarding singing for leaders of faith-based organizations, advising that they suspend or at least decrease use of choirs and musical ensembles as well as congregant singing and chanting.

However, that specific guidance was removed from the CDC website by the end of May. NPR reported that an unnamed federal official said that it was taken down because it had not been cleared by the White House.

On Saturday, the day before the church rally, President Trump’s campaign announced that it was postponing two campaign events that Pence was scheduled to headline in Florida and Arizona this week, “out of an abundance of caution” over the spikes in coronavirus cases in those two states.

In his Sunday remarks at the church, Pence said in part: “As we think about the challenges — the loss of more than 125,000 of our countrymen; when we think of the grief of those families; we think of those that are still struggling with this disease today; those who’ve endured economic hardship in the midst of the challenges we face — let’s claim that ancient promise that if His people who are called by His name will humble themselves and pray, He’ll do like he’s always done through the long and storied history of this nation. He’ll hear from heaven, and He’ll heal this land. “