There are 35 confirmed cases of COVID-19 in Minnesota, including the first instances of community transmission — evidence the coronavirus is spreading locally.

It was a significant development Sunday, though health professionals have said it was only a matter of time before people were diagnosed who neither were in contact with someone known to be infected or had traveled outside Minnesota.

The three patients with local transmission are residents of Ramsey, Dakota and Hennepin counties, and the Minnesota Department of Health is working to identify people they’ve been in contact with and advise them to stay home.

Now that it’s known COVID-19 has spread in the community, “that means that we know that the number of cases that we’re reporting is fewer than actually exists” and “there are many more cases than have actually come to detection,” said Kris Ehresmann, Infectious Disease Division director at the Minnesota Health Department.

Sunday’s count was 14 more than the day before, and it came with a strong message from Ehresmann: People who are 70 and older, or any age with underlying health conditions that put them at higher risk of severe illness from COVID-19, should stay home.

Younger people are also susceptible: Of the 14 new cases announced Sunday in Minnesota, six were in their 20s and two were 31 years old.

“We really want people to take this seriously,” Ehresmann said. “If we’re going to attempt to slow down the spread of COVID-19 we really need to have people both stay home when they’re sick … and we need to make sure that our most vulnerable community members are not put at risk, and one way that they can do that is to stay home.”

14 NEW CASES, AVERAGE AGE OF 38

Health Commissioner Jan Malcolm said Sunday there aren’t “major clusters” in Minnesota and very few cases have been severe enough for hospitalization. Two people are hospitalized — a Dakota County resident in their 90s who is in stable condition and a person from Anoka County who is in critical condition. The others are recovering in isolation in their homes.

“While most have an identified source of exposure, with the limitations that we’ve discussed on testing capacity nationwide, there’s just much we don’t know about the potential degree of community transmission in Minnesota,” Malcolm said. “… This is the right time to implement our community mitigation strategies.”

Approximately 1,422 people have been tested for coronavirus, according to Sunday information from the Minnesota Health Department.

The new cases discussed Sunday are residents of the following counties: four in Ramsey (total of eight), one in Washington, one in Dakota (total of three), six in Hennepin (total of 12), one in Olmsted (total of two) and one in Waseca. The 14 patients are 20 to 94 years old, with the average age being 38.

“If you’re in your 20s and 30s and feeling invincible, it’s important to keep in mind that you too are at risk for COVID and you need to stay at home if you’re sick, to protect people around you,” Ehresmann said.

The Minnesota Health Department is recommending that gatherings of 250 or more be canceled or postponed, along with smaller gatherings that don’t allow social distancing of 6 feet per person.

Gov. Tim Walz announced on Sunday the closure of Minnesota public schools from Wednesday through March 27.

ST. THOMAS ACADEMY STUDENT QUARANTINED AT HOME

One of the cases announced Saturday involves a Dakota County teenager, and the health department has worked with the school to make notifications.

It was a student at St. Thomas Academy in Mendota Heights who tested positive. His father was found to have COVID-19 last week, leading to the Thursday and Friday closing of St. Thomas Academy and adjacent Visitation Catholic School.

St. Thomas Academy and Visitation are on spring break this week and will remain closed “pending further advice” from the heath department, according to a Sunday statement from the Archdiocese of St. Paul and Minneapolis.

The St. Thomas Academy student “is asymptomatic and currently quarantined at home,” according to a St. Thomas Academy letter.

On Sunday, because the St. Thomas Academy student had been present at Visitation, that school also notified families.

Separately, the Seward Community Co-op in Minneapolis said Sunday a staff member at its Franklin Avenue store tested positive for COVID-19. The employee only worked on Tuesday and is not a cashier. That location is closed for a cleaning company to come in and it will re-open “once we are able to determine that it poses no risk to the community,” the co-op announced.

The American Federation of State, County and Municipal Employees Council 5 said Sunday that there is a potential case of COVID-19 among the union’s staff. The person is in isolation and being tested, according to the announcement.