All public schools in Plymouth, Massachusetts, were closed on Friday so every building and bus in the system could be disinfected over concerns about the possible spread of coronavirus.

However, the Plymouth High School student whose illness, after a class trip to coronavirus-hit Milan, Italy, prompted the deep-cleaning has tested negative for the virus, COVID-19, the school district's superintendent said Friday evening.

"This has been a very trying time for all the families involved," Superintendent Gary Maestas said in a statement. "We look forward to seeing students and staff on Monday in our schools."

Twelve school buildings and buses had been ordered clean after the student began feeling ill on Wednesday night, 11 days after returning from overseas.

"We were answering a 911 call for a patient that had flu-like symptoms," Plymouth Fire Chief Ed Bradley said.

Almost 300 million kids around the world are not able to go to school due to coronavirus concerns, with schools in Plymouth, Massachusetts, closing Friday.

Paramedics rushed him to Beth Israel Deaconess Hospital in Plymouth, where doctors later sent him home to self-isolate.

While it was never clear if the student had COVID-19, given how the deadly virus continues to spread throughout Italy, school officials took added precautions.

Maestas didn't say what did make the student sick.

Maestas initially released a statement saying, "We have been in close contact with our partner school in Milan, and as of this morning, there have been no reported cases of COVID-19. As a precaution, all students and chaperones who have traveled to Italy with the high schools have been asked to stay home and self-isolate."

The district didn't say how many of its students and staff went on the trip.

Several local restaurants say they are struggling with uncertainty brought on by the coronavirus outbreak.

As a result of Wednesday's student illness, school officials hired a professional commercial cleaning service to clean all surfaces that people come into contact with in all Plymouth schools and school buses.