Missouri’s most populous county is limiting crowd sizes, ordering bars to close early and urging parents to teach their children virtually if possible when the school year starts as the number of coronavirus cases soars.

St. Louis County Executive Dr. Sam Page said Monday that the new restrictions would take effect at 5 p.m. Friday. The announcement came one day after the county reported 523 new positive cases for its largest single-day increase. The number of infections is thought to be far higher because many people have not been tested, and studies suggest people can be infected with the virus without feeling sick.

“This is serious,” Page said. “This will overwhelm our community. This will overwhelm our hospitals. The decisions we are making today will not bend the curb for at least three weeks.”

The new restrictions include limiting gatherings to no more than 50 people, rolling back the number of people allowed in businesses, closing bars starting at 10 p.m. and working with business to ensure they are complying with the rules.

“If businesses are not playing by the rules, they should not be open,” Page said.

Page said people waiting for test results must quarantine and that spaces will be found for teachers to quarantine if needed. There also will be a push to ensure health care providers are reporting their testing promptly.

Page also urged parents to strongly consider avoiding in-person schooling for their children unless absolutely necessary.

“Please know that we are trying to take as many steps as we can to flatten the curve and provide a safe option for our parents later this year to have an in-school in classroom setting for their students if they chose that option,” he said. “But even with these steps even with that knowledge it is my recommendation as a parent that parents who can choose a virtual option if it is available. And I know that that virtual options will be difficult for many.”

But he also acknowledged virtual learning wasn’t a good fit for many families.

“Some parents who have childcare needs and some parents who have kids with special needs,” he said. “They need that support structure and that predictability in order for their kids to be able to learn.”