A Sting concert in Liverpool came to a sudden halt Sunday night when a drummer collapsed on stage in front of thousands of fans—yet another disturbing incident in a growing trend of people suddenly falling ill in public since the mass rollout of COVID-19 vaccines in 2021.

Lionel Duke, 58, of Liverpool band The Christians, suffered a cardiac arrest while performing during the On The Waterfront festival at the city’s Pier Head. The band was supporting Sting, the former frontman of The Police, who was headlining the four-day event.

Duke’s vaccination status is unknown, however Sting has made it clear he expects everybody attending his concerts to be fully vaccinated and boosted.

“I would like people to come to my shows to be vaccinated,” Sting said to the BBC. “I’m not going to enforce it, but that’s my desire.”

Emergency medical teams rushed on stage as lead singer Gary Christian called for help. Duke was taken to Liverpool’s Heart and Chest Hospital, where he was placed in an induced coma following surgery.

Witnesses described the moment as “terrifying,” with the performance stopping abruptly and black screens going up around the stage. A sign informed the audience that medical staff were attending to the performer.

Festival organizers confirmed that Sting proceeded with his set later in the evening after receiving the band’s blessing.

Duke’s condition remains critical. The band’s manager described the incident as a complete shock, noting that Duke was “a very fit, regular swimmer.”

While officials have not suggested a cause beyond cardiac arrest, the incident joins a growing list of sudden collapses at live performances, sports events and on TV—a phenomenon that has become impossible to ignore over the past few years.