Dr. Ken Langa, a professor of medicine and co-director of the Institute of Gerontology at the University of Michigan, said that while dementia patients, whose social network tends to be small, may be at lower risk than the overall population of contracting the virus, they can be in greater danger of complications if they get it. Most dementia patients are in the high-risk older population; the Alzheimer’s Association report found that one out of 10 people over 65 suffer from Alzheimer’s. And many have chronic conditions that could make them more vulnerable to complications from the infection, Dr. Langa said.