Students in the Archdiocese of Philadelphia’s 17 high schools are being told to stay home if they are just returning from China, due to concern about the coronavirus, according to a message sent Friday to school families.

“While there is no evidence to suggest the presence of coronavirus in any of our schools, we have implemented the following practices out of an abundance of caution,” wrote Sister Maureen L. McDermott, superintendent of the archdiocese’s secondary schools.

Students returning from China are required to remain home for 14 days following their reentry to the United States, McDermott wrote, citing federal Centers for Disease Control and Prevention guidance that the coronavirus’ incubation period — meaning the time between exposure and the development of symptoms — is two to 14 days.

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If students returning from China are free of symptoms after 14 days, they can return to school. Those who must stay home for 14 days will be provided assignments and academic support, the message states. Any students exhibiting signs of ill health during their 14-day home stay are required to seek immediate medical attention.

The notice said that students, as well as faculty or staff members, should not travel to China for the remainder of the school year. Any student exceptions require written consent from their parents and their school.

Parents living in China are being asked by archdiocesan officials to not visit their children in the United States for the remainder of the school year.

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In addition, international students are being advised to wait until the end of the school year to return to their native country and to arrive back in the U.S. at least 14 days before the beginning of the 2020-2021 school year.

Archdiocese officials could not be reached Friday evening to say how many students might be affected by this policy.

Though more than 200 people globally have died from the infection, in most cases the impact of the virus appears to be fairly mild. According to the CDC, the risk to the general public appears to be low in the U.S., where there have been no deaths and a handful of confirmed cases, all linked to travel overseas.