Florida data shows thousands have COVID-19 antibodies
Florida’s health department released data on Friday showing the results of more than 123,000 people who have received a COVID-19 antibody test — with 5,474 people testing positive for previous infections, or about 4.4% of those tested.
The testing data, reported publicly by the state for the first time, does not reflect the percentage of people in Florida who have had COVID-19 because the antibody tests were not part of a study to measure infections statewide.
Medical experts say it is still unclear if antibodies, produced in the bloodstream after infection, provide any immunity from a second infection. Antibody tests, also known as serology tests, generally require a finger prick of blood and are separate from nasal swab tests used to determine a current infection.
Gigi Gronvall, an immunology expert and professor at Johns Hopkins University’s Center for Health Security, said in an email that the report provides a “convenient snapshot” of those who have tested positive for antibodies. But without a controlled study that follows a carefully selected sample representative of Florida’s population, it’s not possible to use the state’s antibody test results to track the disease’s progress over time.
“Even still,” Gronvall said, “there are some sad indicators of racial disparities in these results, and I hope that more will be done ... so that they can learn who is disproportionately affected by COVID, and what interventions can be taken to diminish spread.”
In the six-page report, test results are broken down by county, and by age, race and ethnicity. The report also includes a list of commercial laboratories that have processed the antibody tests.
Florida’s data shows that Miami-Dade County had the highest total number of people with positive test results, with 1,614 people testing positive or about 7.5% of the 21,400 tested in the county. Of the 14,400 people tested in Broward County, about 4.8% or 697 were positive.
The state’s highest antibody-positive rate was found in Liberty County in the Panhandle, where 1 out of 4 people — or 25% — tested positive. The report reflects a total of 123,552 people tested statewide.
Among those who were tested across the state, African Americans were positive for COVID-19 antibodies at a higher rate than whites and other races. However, fewer blacks were tested than whites and other races.
Among the 1,288 African Americans tested statewide, about 340 or 26.3% were positive for COVID-19 antibodies compared to 1,791 or about 13% of the 13,433 whites who were tested. Of the 2,014 people tested whose race is identified as “other,” about 300 or
14.8% were positive.
Hispanics also were positive for antibodies at a higher rate than whites, although fewer Hispanics have been tested, the data shows. Of the 3,627 Hispanics tested for antibodies, nearly 23% or 832 were positive for antibodies compared to 1,374 or about 14 percent of the 9,953 nonHispanics who were tested.
The antibody testing report released Friday differs from the daily reports the health department produces showing results of molecular tests, which can identify an active COVID-19 infection. Antibodies typically develop about two to three weeks after infection.
Florida’s health department has confirmed a total of 54,497 COVID-19 cases using the molecular tests. A total of 2,413 people have died of COVID-19, according to the state.
State health officials said they will provide a report each Friday on antibody testing, but they have yet to offer insight into Florida’s long-term strategy for antibody testing.
Florida has been conducting antibody testing of healthcare workers, firefighters, police officers and other first responders at drive-thru sites in Miami Gardens, West Palm Beach, Orlando and Jacksonville for about three weeks. Each drive-thru site can test 100 people per day. State officials said they are also distributing antibody tests to hospitals to test health workers.
It’s unclear from the state-provided information where the tests reported Friday were conducted. The antibody report includes more than tests performed on first responders and health workers. It includes data for more than 1,200 children younger than 15, and more than 12,000 people older than 75.
Antibody tests could become a key part of states’ long-term plans for reopening.
Public health experts in Europe have discussed the possibility of an “immunity passport,” documentation that would show if a person has had COVID-19 and could be allowed to return to work or other public places without fear of contracting or spreading the disease.
But the World Health Organization and many public health groups have warned against the idea, saying there is still no proof that antibodies in the blood mean a person is immune to a second infection.