A mostly vaccinated group of elderly residents in South Florida tested positive for COVID-19 after attending an indoor July 4 concert, the South Florida Sun Sentinel reports. The residents, who live at John Knox Village, a retirement community, began showing symptoms over the past week, leading the Broward County Department of Health to provide on-site testing. Photos from the event showed the residents together in a crowded room without masks or social distancing.

The cases have been a mix of symptomatic and asymptomatic, with some reporting coughs and shortness of breath. The village’s CEO wouldn’t say how many residents tested positive but said most symptoms are not severe. The community was one of the first in the country to get the vaccine, with Gov. Ron DeSantis appearing there to promote distribution efforts. COVID vaccines are extremely effective at preventing infection and, if a breakthrough infection does occur, it’s more likely to be mild.