Two weeks of testing showed 6 percent of participants had antibodies against the CCP (Chinese Communist Party) virus, a novel coronavirus that emerged from mainland China last year.
Extrapolated countywide, 165,000 residents would have been infected with the virus, which causes a disease called COVID-19. If true, the actual number of infections is 16.5 times higher than the number of cases confirmed through testing sites and local hospitals.
“We believe that our data sheds new light on what is happening in our community,” Miami-Dade Mayor Carlos Giménez said during a press conference on Friday.
Miami-Dade County officials said they’re 95 percent certain the true amount of infection is between 4.4 percent and 7.9 percent of the population, or between 123,000 and 221,000 residents.
About 1,800 people have been tested so far through the testing program, which is ongoing. The initial 400, tested during a pilot phase, were not counted in the total. Along with testing on new people, officials plan on conducting follow-up tests on people who tested positive for antibodies.
University of Miami Miller School of Medicine researchers are working with the county on the program.
Antibody tests measure proteins in the body that are produced when people are exposed to the CCP virus. If people have antibodies, they were infected with the virus but have since recovered. They may be immune to reinfection. That is still being explored by researchers.
The results from Florida are similar to recent antibody testing conducted elsewhere, including in New York.
Recent antibody testing there found a 13.9 percent infection rate, including 21.2 percent among New York City residents.
More than half of the people who tested positive to antibody screening showed no symptoms in recent weeks, Giménez said. According to a growing body of evidence, a number of people who contract the CCP virus show no symptoms but can still transmit the illness to others.
The mayor said social distancing measures will need to remain in place during phased reopenings, such as maintaining 6 feet of distance from others and using masks or other face coverings.
“We want to get back to normal, but we can only do so if people take personal responsibility and follow the rules,” he said.