Colorado schools will have to close for 72 hours if a student or staff member is identified as having COVID-19, the disease caused by the new coronavirus, and schools that have three or more cases will have to close for 14 days, under new rules issued Wednesday by Gov. Jared Polis. If a district has three or more schools affected, the state will recommend the district close for 14 days.

The orders come as the World Health Organization declared the spread of the new coronavirus a pandemic and a day after Polis declared a state of emergency in Colorado. Around the country and the region, more significant restrictions are being put in place, and organizations are canceling conferences and gatherings. Many school districts in the Seattle area, where there are hundreds of cases, will be closed for at least the next two weeks, and Washington Gov. Jay Inslee banned gatherings of more than 250 people in the three hardest-hit counties.

Colorado officials are not calling for proactive school closures or banning public gatherings at this time. However, organizers have canceled events ranging from this weekend’s Rocky Mountain Early Childhood Conference to the Colorado Education Association’s March 19 teacher rally. Denver Parks and Recreation canceled all programming and events, though centers and pools remain open.

As of Wednesday, Colorado had 33 presumptive positive cases in nine counties, doubling the number. State public health authorities have confirmed that community transmission — cases that do not involve known travel to an affected country or known exposure to an infected person — is occurring in Colorado’s High Country and believe it is happening in other parts of the state.

Polis said Colorado could be at a “tipping point” for community transmission.

“This is getting worse before it gets better,” he said.

The 33 cases include nine in Pitkin County; six in Denver; four in Eagle County; three each in Arapahoe, Jefferson, and Douglas counties; two in Gunnison County; and one each in Larimer, El Paso, and Summit counties.

On Wednesday, a Denver elementary school became the first public school in the state to close in response to COVID-19. Cory Elementary, which serves 400 students in southeast Denver, closed because a parent has “a confirmed case” of coronavirus. The school will remain closed Thursday as it awaits test results from the parent’s two children.

Two Denver private schools have also closed. St. Anne’s Episcopal School in Denver closed for cleaning after a parent of a student there tested positive for the virus. Mullen High School closed for cleaning even though the school does not have any confirmed cases.

Two students at Denver’s East High School have been under quarantine after coming into contact with a family friend who was later diagnosed with COVID-19. Teachers were notified on a Friday evening, and a letter was sent to families on a Saturday. Denver Public Schools did not close East, opting instead to clean the school over the weekend.

The purpose of school closures is not just to keep children safe. Younger people do not seem to be at high risk of serious illness, something researchers are still trying to understand better. Research has found that closing schools earlier in an outbreak is more effective at limiting the spread of disease. Closures may also be necessary due to staff absences.

However, state officials are not recommending that schools or child care centers close before they have any known cases among their population. Officials are recommending that schools increase cleaning, cancel or postpone events that would bring large crowds together, cancel larger classes that mix students from different classrooms, and get rid of incentives to come to school sick, like perfect attendance awards.

Schools should also develop plans for remote learning and providing lunches to students if possible, the guidance says. Closing schools comes with significant trade-offs for students, especially those from low-income families. Some may depend on school lunch or not have safe places to stay during the day.

The complete school guidance issued by the Colorado Department of Public Health and Environment can be found here.

Any school or child care center with a confirmed case in a student or staff member must close for at least 72 hours for cleaning. A second case within 30 days would require another 72-hour closure. Any school with three or more confirmed cases within 30 days will have to close for at least 14 days.

And if three schools in a district have confirmed cases within 30 days, all schools in the district would have to close for at least 14 days for cleaning, testing, and public health investigation.

Districts will have more discretion in how to handle cases involving relatives and caregivers of students. If a parent tests positive, for example, officials should figure out if the parent was on campus recently, and the parent’s child should be tested. Schools may choose to close for 24 hours while awaiting test results, the guidance states.

Other factors that could go into a closure decision include whether a family has students at multiple schools and whether staff travel between multiple buildings, as is common in many districts.

Colleges and universities in urban areas and parts of the state with outbreaks should move to online instruction and encourage students who can do so to travel home for spring break and remain there, the guidance says. At the same time, dorms and campus health clinics should remain open for students who can’t go home.

Institutions in rural areas without outbreaks should prepare for the possibility of going online should it become necessary, the guidance says.

Many public and private Colorado colleges and universities are moving classes online in response to the coronavirus. Some are also extending their spring break.

The public colleges include University of Colorado system, with campuses in Boulder, Denver, and Colorado Springs; Colorado State University in Fort Collins; the Colorado School of Mines in Golden; Metropolitan State University in Denver; the University of Northern Colorado in Greeley; and Fort Lewis College in Durango.

The private colleges include the University of Denver, Colorado College in Colorado Springs, and Naropa University in Boulder.

Chalkbeat reporters Melanie Asmar and Yesenia Robles contributed to this report.

This story has been updated to include more plan details and to reflect that Colorado School of Mines is a public institution.