Twelve states so far have shut down all K-12 public schools in an attempt to curtail the spread of the 2019 novel coronavirus. Officials in Kentucky, Maryland, Ohio, Michigan, Virginia, Pennsylvania, Washington, Illinois, New Mexico, Wisconsin, Florida, and Alabama announced that all schools in their states will close for several weeks because of the pandemic. Washington State Gov. Jay Inslee announced Friday that in addition to closing all schools until the end of April, he is going to “restrict activities” at colleges, saying there would be no in-person courses.

“The circumstances of this case indicate that we are entering a new phase of this crisis in our state,” Maryland Republican Gov. Larry Hogan told reporters Thursday after 12 people tested positive for the virus. “We should expect the number of cases to dramatically and rapidly rise. Our primary focus is now turning from containment to aggressively working to mitigate and limit the spread of the virus.”

Los Angeles Unified, the second-largest school district in the nation, also announced it would close its 900 campuses serving about half a million students. The District of Columbia said on Friday that schools would close until the end of March, shifting April spring break to next week. Many cities, including San Francisco, Denver, Atlanta, Austin, Dallas, Houston, Seattle, and New Rochelle in New York state have also decided to close schools and practice distance learning as the pandemic worsens in their areas.