A medical worker draws blood at a free coronavirus antibody testing event in Los Angeles on Wednesday.

A medical worker draws blood at a free coronavirus antibody testing event in Los Angeles on Wednesday.

A medical worker draws blood at a free coronavirus antibody testing event in Los Angeles on Wednesday.

LOS ANGELES, CALIFORNIA – AUGUST 05: A medical worker draws blood at a free COVID-19 SARS-CoV-2 serology antibody testing community event, hosted by GUARDaHEART Foundation and Baldwin Hills Crenshaw Plaza, at Baldwin Hills Crenshaw Plaza on August 05, 2020 in Los Angeles, California. (Photo by Matt Winkelmeyer/Getty Images)