BOSTON—The patient in Room 5 had one big thing going for her. She was young.
Adriana Rice-Leiva, 31 years old and 7½ months pregnant, also had been in good health. Even in a hospital bed, hooked to machines and deathly ill with Covid-19, her dark hair shined and her skin glowed.
Ms. Rice-Leiva was breathing with a ventilator and kept still…