Doctors cited testing for antibodies, which are produced by the immune system in response to viruses.
The five cases were each in a different county, Dr. Amy Acton told reporters Monday.
“We’re doing a lot more investigation. Our disease detectives are going back to take a look at that and see if they were associated with travel,” said Acton, director of the Ohio Department of Health (ODH)
The antibody testing will let officials “learn more and more about this disease, how long it was here in Ohio, how long it was spreading, as we do more and more testing,” she added.
It wasn’t clear who was carrying out the antibody testing. An ODH spokeswoman told The Epoch Times that the department hasn’t carried out any antibody testing.
Ohio Lt. Gov. Jon Husted said at the same press briefing that the testing was made possible through NetJets, a company that helped obtain the tests from China. The tests were from Cellex.
The CCP (Chinese Communist Party) virus, which causes the disease COVID-19, emerged in China last year.
If the results are confirmed, they’d be the earliest signal of CCP virus spread in the United States. California authorities previously said autopsy results showed a patient died with COVID-19 on Feb. 6.
Symptoms take between 2 and 14 days to appear after infection.
Antibody tests “can help healthcare professionals identify individuals who have overcome an infection in the past and developed an immune response,” according to guidance from the Ohio Department of Health for employers.
The testing results may, in the future, help determine that patients are no longer susceptible to the CCP virus, letting them return to work even in areas with restrictions.
Acton told businesses using antibody tests that antibodies may not be detected by the tests in the early days of an infection.
She said employers should only buy tests approved by the Food and Drug Administration.