Black women have long faced racism in healthcare. COVID-19 is only amplifying it.

By the time Rana Zoe Mungin called 911 on March 19, she could hardly breathe. The 30-year-old social studies teacher had been at home in Brooklyn, sick with a fever, cough, and shortness of breath for nearly a week. Days earlier, she had gone to urgent care, worried she had signs of COVID-19, but the clinic was short on tests and treated her for an asthma attack instead.

Mungin’s condition worsened, and because she was too weak to take the subway to the nearest hospital, she called 911. When...