NASHVILLE, Tenn. (AP) _ Health officials in Tennessee have linked a small coronavirus cluster to last month’s meeting of the Southern Baptist Convention, Nashville’s first large-scale conference after lifting restrictions on gatherings, The Tennessean reported.

Metro Public Health Department epidemiologist Leslie Waller said eight to 10 infections have been detected among the more than 18,000 attendees, but the cluster is almost certainly larger. It is difficult to know how many other cases there might be because most attendees live outside the state, Waller said. The Centers for Disease Control and Prevention has issued an alert asking health officials in other states to contact Metro Health if they discover more infections that trace back to the event.

Jonathan Howe, a spokesman for the Southern Baptist Convention Executive Committee, said the organization has not alerted attendees about the cluster and is working with city and state health officials to identify its next steps.

Nashville lifted its mask mandate and gathering restrictions a month before the two-day annual meeting of the nation’s largest Protestant denomination in mid-June. Attendees packed tightly into an 18,000-seat convention hall that included only a small section designated for people who wanted to wear masks.

The gathering may also have attracted a crowd with a low rate of vaccination. In a March poll by The Associated Press-NORC Center for Public Affairs Research, 40% of white evangelical Protestants said they likely won’t get vaccinated, compared with 25% of all Americans, 28% of white mainline Protestants and 27% of nonwhite Protestants.

The Baptist event was a long-awaited revival of Nashville’s lucrative convention industry. Before the pandemic, conferences like it accounted for 40% of Nashville’s tourism businesses, according to the Nashville Convention and Visitor’s Corp.