Q. When my spouse gets a bad cold or the flu, is there anything I can do to reduce the likelihood that I will get it? Would it make a difference if I avoid sleeping in the same bed or avoid handling the same objects (nearly impossible)? Assuming I am not going to move out of the house, are there any smaller steps that could help? Once symptoms are evident, is it already too late?

A. There’s no question that it’s harder to protect yourself when the sick person is living inside your house.

Washing the hands frequently is of course key to preventing illness, both inside and outside the home, said Dr. Robin Thompson, an internist at ProHealth Care Associates in Huntington, N.Y.

“Avoiding close contact is probably helpful, but not a guarantee,” she said. Sleeping in the same bed will increase your chances of contracting your spouse’s illness but often can’t be avoided, Dr. Thompson said. “You can’t move out of the house.”