GENESEE COUNTY, MI -- Four cases of COVID-19 have been confirmed in Genesee County, the first of the fast-moving virus in the county.

John McKellar, county health officer, reported the cases in a news conference Friday, March 20, saying they involve three women aged 15, 22 and 35 and a man, age 54.

“This is a very early and ongoing investigation ...,” McKellar said. “These individuals are stable and self-isolating at their homes. We know at this point of no travel history that was reported with any of these cases. There are no known exposure locations in Genesee County at this time.”

The health officer did not release the locations of the individuals who tested positive for coronavirus, and said the county Health Department has started contact tracing in each case -- two of which were reported by their health care providers to the county late Thursday, March 19, and two more of which were reported Friday.

The county then reported the cases to the Michigan Department of Health and Human Services.

“After interviewing these patients, we learned who they have had close contact with," McKellar said. "We (will) reach out to contact those individuals and advise as appropriate -- in most cases it will be that those individuals self-isolate at their homes for 14 days.”

Although the investigation of the four county residents’ cases is early, he said the Health Department doesn’t believe that the cases are related and said each had a different health care provider.

“All four had an outpatient health care experience -- either a physician’s office or a health clinic type of a situation and a physician determined they should be tested," he said.

The 15 year old is believed to be a high school student, but McKellar said he didn’t immediately know when the patient was tested or how long it has been since the student was in school.

The state on Thursday reported what it initially said was the first positive COVID-19 case in the county but later said the report was an error and that the county still had no presumptive cases.

Statewide, DHHS released updated figures Thursday that showed a rise in the total statewide cases to 334. The state updates case numbers daily at 2 p.m.

The county has been expecting its first coronavirus cases as the number of tests submitted to a state lab has risen, because of increased commercial testing and because of increased capability at labs that process tests.

MDHHS is currently receiving reports from commercial labs LabCorp and Quest Diagnostics and several clinical labs including Sparrow Hospital in Lansing, the Beaumont Hospital Network, Henry Ford Health System and the MDHHS Bureau of Laboratories.

Of the four Genesee County cases, three were processed by commercial labs and one by the state, county officials said.

“I would like to say that this news is probably frightening to many of us Genesee County residents,” McKellar said in making the announcement at the county administration building, where visitors were screened at the entrance door to be sure they did not have fever, one of the symptoms of COVID-19. “I would also like to say that today, I and all of us should really be doing nothing different than we were doing yesterday .... We have all been -- for a number of days and weeks -- preparing and practicing the important preventative behaviors like social distancing," hand-washing and staying away from crowds.

The four new cases of coronavirus do not include an employee of General Motors’ Flint Assembly plant, who also tested positive for COVID-19 and may not be a resident of the county, the health officer said.

GM said Thursday that the employee had been absent from the job since March 5 and sped up plans it had announced earlier this week to shut down the truck plant.

Speaking at a separate news conference with Flint Mayor Sheldon Neeley Friday, Dr. Bobby Mukkamala said he was "a little surprised it took us this long to get to four cases in Genesee County but that’s a matter of testing.”

“In an ideal world we’d have tests ready to go, screen them and then isolate them if they’re positive for the disease,” said Mukkamala, a Flint Township doctor and president of the Michigan State Medical Society.

The development of COVID-19 test kits was slow, “so we fell behind as a country,” Mukkamala said.

“Until these manufacturers make these tests kits more readily available, we must be prudent with who we are testing,” the doctor said.

Mukkamala said he expects test kits to be readily available in a few weeks.

McKellar said there have been increases in testing due more laboratory capacity to process tests and personal protective equipment available in the county during the past 48 hours.

“We’re starting to see more cases all of a sudden being reported out,” resulting in higher numbers, he said.

MLive reporter Zahra Ahmad contributed.

Friday, March 20: Latest developments on coronavirus in Michigan

State mistakenly reports coronavirus case in Genesee County