UPDATE: Health officials said Tuesday that the exchange student has tested negative for coronavirus, but William Penn still is dealing with fallout.

Philadelphia health officials are investigating whether a Chinese exchange student at William Penn Charter School may have contracted coronavirus, the respiratory illness that has sickened thousands and killed 80 people in China, where it originated. The school later told parents that it was ending the exchange program.

The possible victim was among a group of 18 high school students and three adults from China who are visiting Penn Charter. They had a connecting flight in Wuhan, the epicenter of the outbreak, on the way to John F. Kennedy International Airport in New York earlier this month, Sharon Sexton, a spokesperson for the school, said in a statement.

“Health officials have informed the school that the exposure time in Wuhan was limited, and it is important to know that many other common respiratory viruses are circulating in China and here in the United States at this time, so the student’s illness is more likely to be caused by one of those viruses,” Sexton said.

The exchange students arrived at the school last Tuesday and will return next Tuesday, she said.

On Monday night, 6ABC reported that the head of Penn Charter sent a letter to parents notifying them that he was ending the exchange program.

“Although we have not been advised that it is necessary or advisable for us to cancel the exchange for medical or public health reasons, I make this decision because of the following factors,” Darryl J. Ford wrote in the letter, posted on 6ABC’s website. He cited parent and student concern, the disruption to the educational program, uncertainty about when the school will learn about the test results, the media presence Monday at the school, and reports citing the Chinese government as saying the virus can be spread even though a person is not showing symptoms.

“Penn Charter will be open [Tuesday], and we look forward to resuming our normal, robust program with a full complement of students," Ford wrote.

More than 100 people in 26 states have been investigated for possible infection with the virus. Of that group, five have been confirmed as having the illness — all after traveling in the area of Wuhan, the Centers for Disease Control and Prevention said. Also, 32 have tested negative, and the rest of the 110 have not yet had their cases resolved, said Nancy Messonnier, director of the CDC’s National Center for Immunization and Respiratory Diseases.

Health officials said Americans should be far more concerned about the flu, which has claimed at least 8,000 lives this season. That’s a typical toll, though many in the United States avoid getting a flu shot. No one in the U.S. has died of coronavirus.

The Philadelphia Department of Public Health was notified of the potential case on Friday. The student sought medical attention in Montgomery County, and health officials there sent samples to the state for testing, said James Garrow, a spokesperson for the city’s health department. Results are expected this week.

Sexton said the student’s symptoms had improved since last week.

The symptoms of coronavirus are similar to respiratory viral infections or the influenza virus — cough, fever, and shortness of breath. Coronavirus symptoms are mostly respiratory, without the muscle aches and fatigue common with the flu.

The CDC has said the current threat to the U.S. is low, but in an effort to control an outbreak, the guidelines for referring a case for further testing are broad: basically anyone who has traveled to China and is experiencing flu-like symptoms, Garrow said.

“This is a rapidly changing situation. The guidance will change from day to day. We wouldn’t be surprised if we did get a case or two here,” Garrow said.

The city health department has dispatched doctors to the East Falls school to talk to parents about coronavirus and how to take precautions against infection.

“The recommendations are no different for the flu at this point,” Garrow said.

The CDC recommends that anyone suspected of having a coronavirus infection be isolated to avoid infecting others.

For everyone else, the CDC recommendations for protecting against infection are similar to precautions against spreading typical winter illness: cover your mouth with the inside of an elbow when you sneeze or cough, wash your hands frequently, and stay home if you feel sick.

Face masks, like those used by doctors during surgery, may be helpful if worn by someone who is sick in order to keep germs from spreading, but science has not shown them to be effective in protecting healthy people from getting sick, Garrow said.

“Whenever you get in a situation where there’s a novel virus ... it’s scary,” Garrow said. But “the flu is worse, and it is here, and it is spreading throughout the city,” he said.

Six people have died from the flu here this season, he said. He encouraged everyone to get a flu shot.

Still, the health department is keeping a close eye on coronavirus, he said.

Chinese officials have identified more than 2,744 infections and 80 deaths from the virus, which is believed to have originated in a large animal market in Wuhan.

The five U.S. residents with confirmed infections live in Arizona, California, Illinois, and Washington. Five U.S. airports are screening passengers from China to ensure they don’t have symptoms.

As area college students return from winter break, administrators are also being vigilant.

Temple University emailed its students from China — even though not all returned home during the break — as well as any faculty and staff known to have traveled to China. The email summarized the CDC advisories about coronavirus, symptoms, and what to do in case of illness, said Mark Denys, Temple’s senior director of health services.

About 1,500 Temple students are from China, accounting for just over 40% of the university’s international student population, according to Temple’s 2017-18 fact book.

Temple has not been notified of any potential cases, but wants students, faculty, and staff to know what to do if they suspect illness, Denys said. The school’s health service has added to its seasonal flu and cold public health campaign to also alert students about coronavirus, with additional information on its website.

“Right now, there’s no reason to have great concern. It’s something to monitor and keep an eye on,” he said.

Staff writers Tom Avril and Robert Moran contributed to this article.