Ms. Avondoglio and her sister placed their mother, who has Alzheimer’s disease, in a nursing home a few months before the pandemic began. In the beginning, they used to visit her every day and she seemed happy, Ms. Avondoglio said.

But since the coronavirus swept through northern Italy in early 2020, killing thousands of residents in homes, she has been able to visit her mother only once a week, at best, and can speak to her for half an hour through a glass door. Her mother has stopped smiling or talking, she says.

With Covid-19 cases rising fast in much of Europe, and Italy fighting to slow down the Omicron variant that is accelerating in other parts of the continent, many nursing homes have suspended family visits altogether during the Christmas holidays in a pattern that foreshadows the worst fears of families elsewhere, too.