Updated at 11:40 a.m. ET

The number of people with the coronavirus in the U.S. more than doubled over the weekend, from 260 on Friday to 566 on Monday, causing school closures and other disruptions to daily life as the virus spread to new parts of the country.

Financial markets have been rattled by the outbreak and a shakeup in the oil market, and trading on the New York Stock Exchange was halted for 15 minutes Monday morning when the S&P 500 index plummeted 7% just minutes after the open of business.

Worldwide, there are more than 110,000 COVID-19 cases, including more than 7,000 in South Korea, Italy and Iran, according to a dashboard created by the Johns Hopkins Whiting School of Engineering. France, Germany and Spain are each now reporting more than 1,000 cases.

As health officials prepare to take infected people off a cruise ship in Oakland, Calif., federal agencies are telling Americans to avoid cruise ships altogether.

“U.S. citizens, especially with underlying conditions, should not travel by cruise ship,” the State Department said on Sunday.

“As the outbreak of COVID-19 continues, there remains a risk of infected travelers and crew boarding cruise ships,” the Centers for Disease Control and Prevention said.

Trump had wanted Grand Princess passengers to stay on board

The Trump administration’s warnings about cruise ships come as the Grand Princess moves from its holding position 10 miles off the California coast to an industrial dock in Oakland, where it is expected to begin unloading passengers Monday.

The Grand Princess has been sailing in circles off the coast since late last week after a passenger from a recent trip died from COVID-19 in Placer County, Calif. At least one other case, in Nevada, has also been linked to that same voyage.

The ship has 3,533 people on board — including at least 21 who have tested positive for the coronavirus, out of 46 people who were in the first round of testing.

The passengers will be taken off the ship despite previous comments by President Trump, who said on Friday that he would prefer to have all of them stay on board the Grand Princess – because the arrival of more infected people on U.S. soil would raise the country’s case total.

“I’d rather have the people stay,” Trump said, while also noting that he left the final decision in the hands of his administration’s coronavirus task force.

“I would rather — because I like the numbers being where they are — I don’t need to have the numbers double because of one ship that wasn’t our fault,” Trump said.

In response to a reporter’s question about that statement, the president said he was not making coronavirus numbers — and the potential to minimize the size of the U.S. outbreak — a higher priority than treating the sick.

“No,” Trump said. “I’m saying whatever it is that takes precedence over the numbers.”

Trump then repeated that he liked the then-current figure, of 240 cases in the U.S.: “I would rather have the numbers stay where they are. But if they want to take them off, they’ll take them off.”

Grand Princess crew’s destination is in limbo

When 2,422 passengers finally get off the ship, a small number will go to hospitals for urgent care. The remainder will be divided into several groups, depending on where they’re from. In addition to Americans, more than 50 nationalities are represented on board, according to Princess Cruise Lines.

The infected people on the Grand Princess include two passengers and 19 crew members. But while the ship’s guests will begin disembarking on Monday, nearly all of its 1,111 crew members will remain on board and sail back out of San Francisco Bay.

“Plans for a crew quarantine are still being determined,” Princess Cruises says.

It will likely take days to accomplish the complicated task of getting passengers off the ship, NPR’s Eric Westervelt reports for Morning Edition.

“Californians are going to be taken to one of two military bases, one north, one south” in the state, Westervelt says.

“Depending on where they’re from, other U.S. citizens are going to be taken to bases in Georgia and Texas. All will undergo a two-week quarantine. And then there are hundreds of foreign passengers. The State Department’s helping to get chartered flights for them. Canada’s sending a plane to collect 200 of its citizens.”

To prevent the coronavirus from spreading, the CDC recommends washing hands with soap and water for at least 20 seconds, or using a hand sanitizer if a sink isn’t available. The World Health Organization says people should wear face masks only if they’re sick, or caring for someone who is.

“For most people, COVID-19 infection will cause mild illness; however, it can make some people very ill and, in some people, it can be fatal,” the WHO says. “Older people, and those with pre-existing medical conditions (such as cardiovascular disease, chronic respiratory disease or diabetes) are at risk for severe disease.”

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