A researcher takes blood samples from a patient as she participates in a COVID-19 vaccine study last month at the Research Centers of America in Hollywood, Fla.

Laymis Alvarez (R) takes blood samples from Heather Lieberman, 28, as she participates in a COVID-19 vaccine study at the Research Centers of America (RCA) in Hollywood, Florida, on August 13, 2020. – So-called phase three vaccine clinical trials, in which thousands of people take part in the final stages, are gaining traction in Florida. With more than half a million cases and over 9,000 deaths, Florida ranks second in the US in total cases behind California, making it an ideal place to carry out the trials. That has led to a flurry of activity at the RCA, a private center carrying out clinical trials in Hollywood, 25 miles (40kms) north of Miami. (Photo by CHANDAN KHANNA / AFP) (Photo by CHANDAN KHANNA/AFP via Getty Images)