DEAR DR. DONOHUE: When can I expect to catch my annual cold? Midwinter? How long is a person with a cold infectious to others? I want to be responsible about not spreading colds, but I’m not sure my boss is happy with me taking time off for having one. It sounds like a wimpy excuse. How do I tell cold symptoms from more serious things, like the flu? — R.D. ANSWER: Colds aren’t such wimpy things. They cost billions of dollars in lost work time and in over-the-counter medicines. Your boss might be more amenable to allowing workers to take time off with a cold if he or she realized that one cold patient can infect many, many workers. Colds have two peaks, one in the fall and another in early spring. However, you can catch one at any time of the year, including summer. People are great spreaders of the cold virus on day three or four of the cold. That’s when virus production is at its highest. They can, however, spread the virus from as early as one day before cold symptoms appear to as long as two to three weeks after the infection. The cold viruses are spread mostly from the hands and fingers of an infected person to the hands and fingers of the noninfected. When the noninfected touch the nose or the eye with a virus-coated finger, the virus has found a new home. Coughing and sneezing also spread the virus, but not as readily as hand transmission.