Twice a day, Bonnie Polin, 78, drives a few miles to visit her husband at his nursing home in Portland, Oregon. She sits with him while he eats breakfast and tells him stories that she knows he probably won’t remember.

“I fell in love with him because he was so damned smart, and now he’s in the end stages of Parkinson’s disease,” Polin said of her husband, Gerald, 83, a retired psychiatrist. “But he’s still as handsome as ever.”

Polin paused early one morning last week when she arrived for a visit and noticed a new sign posted at the entrance. In response to the worsening coronavirus outbreak, officials at the Avamere Crestview of Portland, an adult care facility, like untold numbers of other nursing homes across the country in recent days, had decided to ban visitors.

Polin read the sign twice. Then she darted past it and went looking for her husband. In the nearly 58 years since they got married, the pair had rarely spent a day apart. When Polin found him, asleep in his wheelchair, she grabbed his hand.

She knew she wouldn’t have long.

“Sweetie, I’m not going to be able to come see you for a while,” she recalled telling him.

She explained that there was a serious new virus spreading in Oregon and across the country, and that elderly people were at higher risk — though she doubts he understood any of that. A minute later, a nursing home staff member arrived and told Polin she needed to leave.

She kissed her husband and told him goodbye; he didn't reply.

“I don’t know when I’ll see you again,” she told him, before heading for the exit.

Bonnie Polin usually visits her husband, Gerald, at his nursing home, twice every day. Leah Nash / for NBC News

For Polin and thousands of others with relatives in nursing homes, the coronavirus outbreak has ushered in a painful new normal. After a nursing home outside Seattle became the U.S. epicenter of a deadly outbreak that has killed at least 18 residents, senior living facilities around the nation have begun banning visitors, in the hopes of preventing similar tragedies.

Many nursing homes have been restricting visits from people with flu-like symptoms and those who have recently traveled abroad. But in recent days, as the number of confirmed coronavirus cases in the U.S. has grown, many facilities announced that they would begin prohibiting social visits altogether.

“As every day unfolds, it becomes clearer that the skilled nursing sector and the assisted living sector face one of the most significant challenges, if not the most significant challenge, in our histories,” said Mark Parkinson, president and CEO of the nursing home trade group American Health Care Association, which Tuesday announced new national guidance recommending that nursing homes prohibit visits from anyone other than health care providers and other essential workers. “The evidence has become overwhelming that the mortality rate to COVID-19 for people that live in our buildings is shocking.”

Although many patients have reported only moderate symptoms, experts say people over the age of 70 are at serious risk of respiratory failure or death. Parkinson said experts were telling him that the death rate for people over the age of 80 might well exceed 15 percent, though government officials say it won’t be possible to calculate a true mortality rate until far more people are tested.

On Monday, New York Gov. Andrew Cuomo announced that state officials had barred visitors from senior living facilities in New Rochelle, a New York City suburb at the center of an emerging outbreak in the region. Later that evening, the Centers for Disease Control and Prevention issued national guidelines for nursing homes, including a recommendation to limit or end social visits from loved ones.

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

Public health officials say these drastic measures are needed to slow the spread of the coronavirus among those most vulnerable to it.

Dorothy Campbell and her son, Charlie Campbell, talk through a window with her husband, Gene Campbell, at the Life Care Center outside Seattle. David Ryder / Reuters

As the outbreak worsened at the Life Care Center in the suburbs of Seattle last week, news reports revealed the tragic consequences that can follow when a nursing home is put on lockdown — a grim foreshadowing of what experts worry could be repeated across the country in the coming weeks.

Some of those cut off from their elderly loved ones at Life Care said they were struggling to learn basic details about what was happening in the facility. Others said they feared they would never see their parents or grandparents again, given their poor health. Photos of a gray-haired woman standing at a window, trying to talk to her quarantined husband on the other side of the glass, made national headlines.

Do you have a story to share about your experience with nursing homes during the coronavirus outbreak? Contact us

Bryan James, an epidemiologist at the Rush Alzheimer’s Disease Center in Chicago, said nursing homes are probably doing the right thing by restricting access until the outbreak is brought under control. But those decisions come at a cost, said James, who studies the way people’s social connections affect their health as they age.

“I think that by isolating people and saying that their family members can’t come to see them, you can very well see scenarios where people begin losing a sense of purpose in their lives,” James said. “That social connectedness is incredibly important in keeping people going every day and keeping people healthy.”

James said relationships with friends and family help people stay mentally sharp as they grow older. He worries that prolonged restrictions on nursing home visits could be devastating for some residents, particularly those already in very poor health. Some, he said, might be forced to spend their final moments alone.

“We already have the problem of people dying alone in this country at such high numbers,” he said. “And now I worry that we’re going to have even more people dying alone in hospice without their loved ones next to them, even though their families desperately want to be with them.”

Full coverage of the coronavirus outbreak

Yvonne Michael, an epidemiologist at Drexel University’s Dornsife School of Public Health in Philadelphia, said nursing homes that ban visitors might need to plan additional social activities to keep residents from feeling isolated.

But that won’t help family members on the outside.

“At the end of the day, it might be harder for the person outside the nursing home than the one inside of it,” Michael said. “For the family members on the outside, that sense of hopelessness — of not being able to be with their loved one who needs them — could also be devastating.”