Florida’s antibody tests suggest little spread

The first statewide results of COVID-19 antibody tests were released Friday and they appear to provide hope that the disease is not more widespread in Florida than previously known.

The state Health Department report showed 123,552 people have had these blood draws — also known as a serology testing — and 5,474, or 4.4%, were positive.

This antibody screening, which began more than a month ago, is supposed to tell whether a person has had COVID-19 or was exposed to the virus long enough to develop some measure of an immune response.

These are not diagnostic tests, or the familiar nasal swabs that show if you are currently infected. There have been nearly 1 million people in Florida who have been swabbed since the outbreak began, with 54,497, or 5.5%, testing positive as of Friday.

The state antibody test report also provided county-by-county result breakdowns. South Florida, which has had more known infections than anywhere else in the state, has had 44.8% of the blood tests.

In Miami-Dade County, 21,402 people have been tested for antibodies. Of those, 7.5%, 1,614 people, were positive.

In Broward, 14,402 people were tested, with 697, or 4.8%, positive. And in Palm Beach County, there were 19,571 tests, and 797, or 4%, came back positive.

Medical experts say they don’t know how long antibodies will protect people from getting the virus in the future. But the testing can indicate the percentage of the population that has had the virus, perhaps without realizing it because of a lack of a cough or other symptoms.

Also, when the antibody test is given to a larger population, the surveillance can help a school, county or workplace learn what percentage has immunity to the virus.

Officials say they want to ramp up the testing. The data report, which notes that the results came from over 100 laboratories, is supposed to be updated each Friday on the health department’s website.

In Miami-Dade, a random countywide surveillance test for antibodies was launched in April to track the spread of the coronavirus.

About 60% of the 1,100 people tested for antibodies by University of Miami researchers, in partnership with the county, had been infected with the virus even though they had no symptoms. About the same percentage of the 300 Hialeah first responders who were tested and had no symptoms also had antibodies

Medical experts advise using the antibody blood test results in combination with traditional tests done with swabs that give positive or negative results.