University Hospital in Newark, New Jersey, is besieged with COVID-19 patients packing its intensive-care unit, where rooms have been improvised from plastic sheeting and staff have fallen victim to the disease. The U.S. Army is reinforcing its defenses.

Capt. Jamie Dowd, a nurse who has treated ghastly trauma in Syria and Iraq, was sent to the hospital on a 30-day mission with 24 other troops to help fight the worst wave of COVID-19 cases since the deadly spring of 2020. Plucked from Fort Polk in Louisiana, Dowd last week peered out from the shadows of a room in the Newark progressive-care unit.

“We’re fighting COVID like it’s our enemy in battle,” said Dowd, standing before the officer in charge as he conducted his morning rounds. Behind her, an elderly patient lay, eyes closed, hooked up to machines that translate vital signs into an eerie melody.