Other caregivers ran into trouble accessing health care, either for themselves or their loved ones. Ora Larson, 82, was scheduled for back surgery in the spring of 2020 in St. Paul, Minn., and was looking forward to relief from the disabling pain of spinal stenosis. Then, as hospitals filled with Covid patients, her operation was postponed until October, then delayed again.

As she waited, “her ability to get all kinds of therapy went away,” said her daughter, Susan Larson, 57. “She couldn’t go to exercise, or have a physical therapist or trainer come to the house, so she got weaker and weaker and her pain increased.”

As Ms. Larson watched her lively mother grow depressed and lose much of her ability to walk, “I felt stressed in the way you do when you’re not sure what your next move is going to be,” she said. Her mother finally underwent surgery in March and is recovering well.

Further studies will reveal more about the ongoing effects of Covid on caregivers. Perhaps they adapted as the pandemic ground on, and their stress abated. Some welcome the meaning and purpose that comes with helping family members.

But the cumulative negative effects, month after month, could also mean greater hardship. And as Dr. Park pointed out, “there would be a greater probability of bereavement and grieving.”

The caregivers interviewed here, and their family members, have been vaccinated and are slowly starting to resume visits and local excursions. But they also recognize that elder care tends to grow more demanding, not less. Those they care for have lost ground physically and cognitively, and may be unable to return to their prepandemic selves.

Stacey Lantagne, 40, a law professor at the University of Mississippi, spent the pandemic with her family in Rhode Island, where she helped care for her grandmother while also teaching a full course load online.