Schools across the United States are canceling trips abroad, preparing online lessons and even rethinking “perfect attendance” awards as they brace for the possibility that the new coronavirus could begin spreading in their communities.

Districts have been rushing to update emergency plans this week after federal officials warned that the virus, which started in China, is almost certain to begin spreading in the U.S. Many are preparing for possible school closures that could stretch weeks or longer, even as they work to tamp down panic among students, parents and teachers.

President Donald Trump has worked to minimize fears about the virus, but on Wednesday he also recommended that schools to start planning for arrival of the COVID-19 virus “just in case.”

“It’s the perfect time for businesses, health care systems, universities and schools to look at their pandemic preparedness plans, dust them off, and make sure that they’re ready,” Trump said Wednesday at a White House news conference.

School letters sent home from Florida to California this week sought to assure parents that, in most communities, the risk of exposure to the virus is still very low. Most suggested the same precautions used to combat the flu: Wash hands frequently, cover sneezes and coughs, and stay home if fever or other symptoms arise.

At schools, cleaning crews have been told to pay extra attention to door knobs, keyboards and other surfaces that students touch through the day. Some districts have invested in handheld disinfectant sprayers that are used in hospitals, Others are adding traditional hand sanitizers in schools and buses.

But even as they work on prevention, schools are also starting to prepare for the worst. Many are making plans to teach students online in case the virus spreads so widely that schools are forced to close. Officials are considering how they would handle large numbers of absences among students or teachers, and how to make up days that could be missed because of the virus.

At least one school temporarily closed Thursday over fears tied to the virus. Bothell High School, near Seattle, canceled classes after a staffer’s family member was placed in quarantine for showing symptoms of possibly contracting the virus. Officials said the school was being cleaned and disinfected “out of an abundance of caution.”

In Miami, public school leaders said they’re readying 200,000 laptops and tablets for students in case buildings close and force classes online. They’re also directing new international students to register at two reception centers instead of at school buildings, where students have typically registered.

“If there is one place where a contagion can actually spread, it could be the schoolhouse,” Alberto Carvalho, superintendent of Miami-Dade County Public Schools, said at a Wednesday news conference. “We are ready. We have protocols in place.”

The district is also among many halting or scaling back foreign travel over concerns about the virus. Miami officials opted to cancel upcoming field trips to Italy and Scotland, while Virginia’s Fairfax County announced it’s suspending all trips to countries where the virus has spread.

In Colorado, where state law requires schools to provide 160 days of instruction per year, education officials are promising flexibility. A Wednesday letter from the state’s education department says it will support schools that “experience a prolonged closure.”

Many districts say they’re awaiting instruction from their state health departments and the U.S. Centers for Disease Control and Prevention. Dallas’ public school district said it’s “reviewing and modifying crisis response plans should an outbreak occur.” Public schools in San Francisco say they’re preparing for exposure of the virus in the district but have “no such cases at this time.”

Districts already have plans to deal with natural disasters, flu outbreaks and other emergencies, and many have planned for widespread infections before, most notably during the 2009 H1N1 influenza pandemic. But most have never faced the prospect of closing for weeks at a time, as has happened in China and other countries working to prevent the virus from spreading.

On Thursday, the virus prompted Japan’s prime minister to ask all of the nation’s schools to close for a month as officials work to control the spread of the new virus in the country.

Some U.S. districts say they already have online learning systems that could be used to provide classes online, but not all schools have that technology. Some have started preparing lessons that could be emailed to students instead or sent home in packets.

If schools are forced to close for long stretches, it could have a heavy impact on students who rely on school meals and for parents who use their schools’ child care programs, said Francisco Negrón, chief legal officer for the National School Boards Association. The group is urging school leaders to discuss those issues with local authorities and develop contingency plans.

The group is also asking districts to reconsider attendance awards that are sometimes given to students who don’t miss a day of class for an entire year or semester. Some schools have previously abandoned the practice amid fears that it encourages students to come to school sick, but some still award gift cards, cash or raffle prizes to students with perfect attendance.

“School districts may want to revisit what it means to have perfect attendance,” Negrón said. “We certainly wouldn’t want sick kids to come to school just because their parents are shooting for that perfect attendance award.”

In many districts, nurses are being asked to serve as the front line in combating the virus. Officials at Denver Public Schools said nurses have been trained on guidelines for managing an outbreak and will be respond to any cases and report to health authorities.

A national association of school superintendents said it’s pressing the CDC for more detailed guidance for schools as they confront the virus. In the meantime, the American Association of School Administrators issued a letter on Thursday telling schools to use “common sense strategies” focusing on prevention.

The letter urged districts to focus on personal hygiene, to develop procedures for reporting cases and to consider canceling trips to any areas in the U.S. or abroad where there have been outbreaks.

“The classroom is a wonderful breeding ground for viruses,” said Dan Domenech, executive director of the group. “That’s why we need to plan what we’re going to do when we begin to see incidents of the coronavirus in our schools and in our communities.”

(AP)