Two paramedics jump out the back of an idling ambulance with Tokyo plates, carefully lowering an elderly woman on a stretcher. The patient, her small face covered with an oxygen mask, disappears behind St. Marianna's automatic doors.

Another suspected COVID-19 patient has arrived.

In the midst of a global pandemic, St. Marianna University Hospital, a Catholic institution in a working-class suburb south of Tokyo, has become synonymous with the virus.