The area’s biggest arts presenter will require patrons to be vaccinated as well as masked when it reopens. The Kimmel Center says the new policy begins with its free “Arts Launch” open house Sept. 18, and will extend into the 2021-22 season.

The mandate will be in place for all performances by the Kimmel’s resident companies — the Philadelphia Orchestra, Opera Philadelphia, Philadelphia Ballet, and others — and in all of its halls, including Verizon, the Academy of Music, and the Merriam Theater, the center announced Monday.

Attendees for public events must show proof of full COVID-19 vaccination at the time of entry. Proof of a negative COVID-19 test will not be accepted, with the exception of children under age 12, who will be required to show a negative PCR test result taken within 72 hours of the event.

All the Broadway shows previously announced by the Kimmel, including Hamilton, are still on.

The new policy requires patrons to wear masks except while actively consuming food or beverages in designated locations. No medical or religious exemptions from vaccines will be granted, said Kimmel chief operating officer Ed Cambron. “Unfortunately, we need to err on the side of everyone being safe,” he said.

The new policy raises a new level of uncertainty for the center, its resident companies, and their financial future. Philadelphia Ballet’s production of The Nutcracker, its annual cash cow, is a family draw, with many patrons under the age of 12. Executive director Shelly Power recognizes that mandatory testing for the younger set could put a chill on ticket sales.

“I know certainly it is an inconvenience, but I suspect most parents want to keep their children safe as well, and as much as we depend on Nutcracker we depend on our community to be healthy.”

She says she hopes that COVID-19 is on the wane or that vaccines will be approved for younger children by December when the show opens.

The Philadelphia Chamber Music Society previously surveyed its listeners, and most patrons said they would feel more comfortable with a vaccine mandate in place.

“A few responses were less than positive,” said PCMS artistic director Miles Cohen, “and we will refund to anyone who feels this policy prevents them from attending.”

Staff members and artists on the center’s stages will also be required to be vaccinated, said the Kimmel’s Cambron, though masks will not be required of performers.