CHICAGO (CBS) — A new case of novel coronavirus has been confirmed in Chicago, and he is not linked to any travel or any of the earlier cases.

The patient is a man in his 60s and is a resident of Chicago, and was hospitalized in serious condition Sunday afternoon, according to Dr. Allison Arwady, Commissioner of the Chicago Department of Public Health.

An investigation by the Chicago and Illinois departments of public health were ongoing Sunday afternoon. But based on what is known, the case has not been linked to any travel or any already-confirmed event.

“Though this may be the first case of community transmission in Chicago, it does not mean widespread transmission of COVID-19 is occurring here,” Arwady said. “It does mean that the surveillance system that we’ve worked to set up to detect any potential community spread is working.”

Arwady noted that the City of Chicago and the State of Illinois were the first to release standard testing. When a sample of people are present to some emergency departments in Chicago with flulike symptoms, but they test negatively for the flu, a sample of those tests have been examined by the state lab.

In addition, people who are already hospitalized with respiratory illnesses and test negatively for other viruses can also be tested for coronavirus at the state lab. That is how this latest patient was discovered, Arwady said.

She said there was no public health reason to share additional geographic details about the case, and the department would address it if there were concerns about exposure.

Arwady noted that community spread has been detected in a growing in a number of countries and areas of the U.S.

“All along, we’ve expected to find more cases,” Arwady said.

She emphasized that the possible community transmission signals how important it is for everyone with flulike symptoms such as fever, cough, or respiratory illness to stay home from school or work and seek medical attention.

City and state officials have not recommended the cancellation of mass-gatherings or other public events. But businesses and community organizations have been urged to review existing emergency operations plans and consider plans for social distancing, Arwady said.

She also emphasized that people who are older and have underlying conditions should consider limiting travel.

Illinois Department of Public Health Director Dr. Ngozi Ezike said even though the seventh case represents possible evidence of transmission in the community, and more cases are expected, officials are not seeing the virus circulating widely in Illinois.

As CBS 2’s Jeremy Ross reported, it is important to point out that this latest patient was given the most severe medical status – serious condition – of any previous patients with COVID-19 in Illinois.

But it is also important to point out the first five people who contracted coronavirus in Illinois have all been described as fully recovered or nearly back to full health.

Meanwhile, Arwady had updates Sunday afternoon on the ongoing investigation at Vaughn Occupational High School.

She said the special education classroom assistant who tested positive for the coronavirus on Friday is now in good condition, and the Chicago Department of Public Health has not identified anyone else from the school with serious illness or who has required hospitalization.

Vaughn will remain closed through March 18 after the woman, in her 50s, tested positive Friday.

Anyone who was at Vaughn at the time the woman was there is asked to stay home until March 18, unless they need medical care or under the direction of the CDPH, Arwady said. People who were not at the school do not have restrictions at this time, even if they have been in contact with someone who was at the school, she said.

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Five other cases of COVID-19 have also been diagnosed in the area.

Officials said the fifth patient is a Cook County resident in his 20s who flew into O’Hare International Airport earlier this month after traveling to Italy.

“The individual acquired the infection while in Italy and is hospitalized at Rush University Medical Center in isolation. Public health officials are identifying and contacting all close contacts,” Illinois health officials said in a written statement.

A fourth person was diagnosed with the virus in the Chicago area at the end of February. Illinois’ patient number four is a woman in her 70s who tested positive for COVID-19.  She is now under at-home isolation and in good condition according to the Illinois Department of Public Health.

She is married to patient number three. He is a man, also in his 70s, who tested positive over the weekend and is now in isolation at home after being treated Northwest Community Hospital. Illinois health officials said the third patient had traveled to states with the virus outbreak.

The two other cases were a couple who tested negative for the virus in February. The couple has been released from the hospital.

Also this weekend, officials said a woman who traveled from Italy to O’Hare International Airport, and then traveled from Chicago to St. Louis by Amtrak train Wednesday of last week, has tested positive for the coronavirus.

On its website, Amtrak said it had received a notification from St. Louis County, Missouri that a customer who has now tested positive for coronavirus traveled on Train 303 on Wednesday, March 4, using stations in both Chicago and St. Louis. It was not known Sunday night how the woman got between O’Hare and Union Station.

The customer did not have symptoms at the time, and was recovering at home as of Sunday, Amtrak said in a memo.