Miami-Dade may want some of your blood to track stealthy spread of coronavirus

Miami-Dade hopes to plot the local spread of the coronavirus through a wave of blood tests that can detect the antibodies produced to fight COVID-19. Researchers say the data could offer the best look yet at people who caught the disease but didn’t know it.

Automated calls to recruit participants could begin as early as Friday, with blood collected early next week. The random “surveillance” testing of 750 people weekly is designed to identify clusters of local spread and measure the extent that COVID-19 has already spread through the Miami-Dade population.

While the disease can be deadly for some and hospitalize even more people, it also can produce symptoms mild enough that people may not realize they have recovered from it.

“All of us are moving in the dark somewhat in terms of understanding the true burden of coronavirus infection in our community,” said Erin Kobetz, the University of Miami cancer researcher helping Miami-Dade plan the sampling effort. Students from UM will screen potential participants contacted at random using demographic information.

A recorded message from Miami-Dade Mayor Carlos Gimenez will invite people to participate. Those selected would report to one of 10 testing sites run by the county’s Fire Department. The tests use new pin-prick tests that can produce results within minutes.

Can I volunteer for the Miami-Dade test?

People can’t volunteer for the free test, but will be selected randomly based on age, where they live and other demographic information. The project is expected to last about six weeks.

Gimenez’s office released a script from the recorded message from the mayor that would-be participants will hear.

“Our community is facing an unprecedented challenge as we grapple to stop this global pandemic. Now, I need your help to stop the spread in Miami-Dade County. That’s why I’m calling you,” Gimenez says, according to the script. “I’m asking you today to participate in a groundbreaking program designed to determine, through free screenings, how many people in Miami-Dade County have been exposed to this virus.”

The test kits were made by BioMedomics, a North Carolina company that recently announced a COVID-19 blood test that has not been reviewed by the federal Food and Drug Administration.

Gimenez’s office has not yet publicly released agreements with providers of the tests. Gimenez said each test costs the county $17, and that Miami-Dade has secured 10,000 BioMedomics tests from a Florida company, Disaster Management Group.

Not all of the tests are for the study. About 3,000 were given to Miami-Dade Fire and Rescue to test first responders, and an additional 2,000 were donated by a foundation for caregivers and people experiencing homelessness in MIami-Dade, said Kevin Lynskey, the county water director, whom Gimenez tapped to head up the testing initiative.

Lynskey said researchers at the University of Washington plan to create an epidemic model for Miami-Dade using the data. The model will forecast Miami-Dade’s infection “curve” and let the county predict where it might see peak hospitalization and demand for intensive-care beds, Lynskey said.

“Current epidemic models fly blind as to the penetration of the disease in the local population,” he said.

The effort makes Miami-Dade one of the first governments in the United States to launch widespread surveillance testing for COVID-19. In Colorado, San Miguel County on Friday announced the results from its first round of blood tests, and it found just 1 percent of its residents tested positive for the disease.

By measuring antibody levels, the tests can detect the likelihood that someone has either recovered from COVID-19 or is suffering from it at the moment. But because antibodies are produced after someone contracts the disease, the tests won’t detect the virus in its earliest stages the way a nasal swab would.

But with the swab tests backlogged and rationed across the country, researchers see the blood, or serological, tests, as the best alternative for rapid and broad looks at how far the coronavirus has spread. Gimenez said the survey could let the county see which communities need more focus or testing resources.

“Our goal is to get a snapshot,” Gimenez said in an online press conference Friday. “Let’s say we find there is a very big cluster in a certain part of Miami-Dade. Maybe we have to take more action in that area of Miami-Dade.”

Why herd immunity matters for COVID-19

Participants will be notified of the results, and told if the tests suggest they may have COVID-19. The FDA says blood tests shouldn’t be used alone to determine whether someone has the disease.

The most encouraging numbers could come from participants who show signs of past infection. People who have recovered from COVID-19 are believed to be immune to the virus, and a large number of them in Miami-Dade would inch the community closer to “herd immunity.”

That’s a state where so many people have already caught the virus that COVID-19 would have a harder time finding new host bodies to spread to. Medical providers also see promise in using plasma from recovered COVID-19 patients to treat people gravely ill with the disease. On Friday, Miami Mayor Francis Suarez, one of the first people in Miami-Dade known to test positive for the disease, donated blood for that effort.

In his press conference, Gimenez said he predicts a significant number of participants in the surveillance study will come back as COVID-19 survivors.

“I expect we’re going to find a ton of people who had no symptoms whatsoever and were already infected,” Gimenez said.

This story was originally published April 3, 2020 at 9:18 PM.