PROFILE OF A KILLER: Unravelling the deadly new coronavirus

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 hospitalised 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 US 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 schools at one point. More than 7 million flights grounded. Countless moments of celebration and sorrow, weddings and graduations, baby showers and funerals, put off, reconfigured or abandoned because of worries about safety. In short, the coronavirus has re-scripted nearly every moment of daily life. And fighting it, whether by searching for a vaccine or seeking to protect family, takes knowing the enemy. It’s the essential first step in what could be an extended quest for some version of normalcy. “There’s light at the end of tunnel, but it’s a very, very long tunnel,” said Dr. Irwin Redlener, director of the National Center for Disaster Preparedness at Columbia University. “There’s a lot we don’t know. But I think it’s absolutely certain we’re going to be adapting to a new way of life. That’s the reality.”

The new coronavirus is roughly 1,000 times narrower than a human hair. But scrutinised through an electron scope, it is clear this enemy is well-armed. Coronaviruses, including the newest one, are named for the spikes that cover their outer surface like a crown, or corona in Latin. Using those club-shaped spikes, the virus latches on to the outer wall of a human cell, invades it and replicates, creating viruses to hijack more cells.

Find a way to block or bind the spikes and you can stop the virus. Once inside a human cell, the virus’ RNA, or genetic code, commandeers its machinery, providing instructions to make thousands of virus copies. But the coronavirus has a weakness: an outer membrane that can be destroyed by ordinary soap. That neutralises the virus, which is why health experts emphasise the need to wash hands. Like organisms, viruses evolve, searching for traits that will ensure survival, said Charles Marshall, a professor of palaeontology at the University of California and self-described “deep time evolutionary biologist.”

“Coronaviruses fit into the standard evolutionary paradigm extremely well, which is if you’ve had some innovation, you get into some new environment ... you get into a human and you do well, you’re going to proliferate,” Marshall said. There are hundreds of coronaviruses, but just seven known to infect people. Four are responsible for some common colds. The new coronavirus, though, has captivated scientists’ attention unlike any in decades.