COVID-19 now in all 50 states after West Virginia confirms first coronavirus case

Two women stroll down the sidewalk wearing masks in response to the coronavirus in Miami, Florida on Sunday, March 15, 2020.

COVID-19 has driven millions of Americans into isolation inside their homes as the novel coronavirus continues to spread across the country, claiming its 50th state Tuesday with the first reported case in West Virginia, the lone holdout in a nation stricken by a rapidly evolving crisis.

West Virginia Gov. Jim Justice on Tuesday said the state had reported its first positive case of the new coronavirus, meaning that all 50 states have now confirmed cases.

MAP: This is where there are confirmed coronavirus cases in the US and around the world

Justice said the confirmed case is in the state's Eastern Panhandle, an area close to Washington, D.C. He did not immediately disclose the county where the illness occurred.

Health officials say that "social distancing" — encouraging people to avoid close contact with others — is a key to slow the spread of the virus and keep U.S. hospitals from being overwhelmed with a sudden deluge of patients.

RELATED: US hospitals fear crippling shortage of ventilators for coronavirus patients

The U.S. surgeon general warned the number of coronavirus cases in the United States has reached a level comparable to what disease-battered Italy recorded two weeks ago — a signal that infections are expected to rise in America.

"We are at a critical inflection point in this country, people," U.S. Surgeon General Dr. Jerome Adams told Fox News. "When you look at the projections, there's every chance that we could be Italy."

RELATED: CDC’s ‘flatten the curve’ graphic shows why social distancing amid coronavirus pandemic is necessary

Two weeks ago, there were 1,700 cases of coronavirus in Italy and the country had reported 34 deaths. Now, Italy is reporting an estimated 25,000 cases and more than 1,800 people have died.

The head of the World Health Organization called the outbreak the “defining global health crisis of our time," noting that testing is the top priority.

“You cannot fight a fire blindfolded, and we cannot stop this pandemic if we don’t know who is infected," said Tedros Adhanom Ghebreyesus . “We have a simple message for all countries: Test, test, test.”

RELATED: What is a pandemic? This is what the WHO’s global COVID-19 designation means

The U.S. has been slower than many countries in ramping up its testing capability, though the White House announced a string of measures last week to speed up the process.

Across the country, health officials, politicians and business leaders talked about "social distancing" and "flattening the curve," or encouraging people to avoid others so as to slow the spread of the virus and keep U.S. hospitals from being overwhelmed with a sudden deluge of patients.