Nursing homes and assisted living centers should take action to curtail most social visits, and should even take steps to keep some employees away, to slow the spread of the new coronavirus, the industry said on Tuesday.

The recommendation follows an outbreak of the virus in the region around Seattle, where five long-term care facilities have been hit with cases, including a facility in Kirkland, Wash., where 18 residents have died.

“The mortality rate is shocking,” said Mark Parkinson, president and chief executive officer of the American Health Care Association. He said that the death rate might well exceed the 15 percent reported in China for people aged 80 and older who were infected.

The challenge of the virus “is one of the most significant, if not the most significant” issues the industry has ever faced, he said.

Industry officials said they are recommending that nursing homes should allow people to enter only if it is essential.

Staff members, contractors and government officials should be asked, “Do you need to be in-building to operate?” said Dr. David Gifford, the health care association’s chief medical officer.

As for family members, he said, “Our recommendation is they should not be visiting.”

Anyone who does visit, he said, should be screened carefully at reception and anyone who has signs of illness should be turned away.