Profile of a killer: Unraveling the deadly new coronavirus

NEW YORK (AP) — What is this enemy?

Seven months after the first patients were hospitalized in China battling an infection doctors had never seen before, the world’s scientists and citizens have reached an unsettling crossroads.

Countless hours of treatment and research, trial and error now make it possible to take much closer measure of the new coronavirus and the lethal disease it has unleashed. But to take advantage of that intelligence, we must confront our persistent vulnerability: The virus leaves no choice.

“It’s like we’re in a battle with something that we can’t see, that we don’t know, and we don’t know where it’s coming from,” said Vivian Castro, a nurse supervisor at St. Joseph’s Medical Center in Yonkers, just north of New York City, which struggled with its caseload this spring.

Castro had treated scores of infected patients before she, too, was hospitalized for the virus in April, then spent two weeks in home quarantine. As soon as she returned to the emergency room for her first shift, she rushed to comfort yet another casualty -- a man swallowing the few words he could muster between gasps for air.

“It just came back, that fear,” she said. “I just wanted to tell him not to give up.”

The coronavirus is invisible, but seemingly everywhere. It requires close contact to spread, but it has reached around the globe faster than any pandemic in history.”

COVID-19 was not even on the world’s radar in November. But it has caused economic upheaval echoing the Great Depression, while claiming more than 570,000 lives. In the U.S. alone, the virus has already killed more Americans than died fighting in World War I.

Even those figures don’t capture the pandemic’s full sweep. Nine of every 10 students worldwide shut out of their...