2. Why isn't there a cold vaccine?

The common cold can be caused by nearly 250 different viruses. It's just too difficult for scientists to prepare a vaccine that protects against all of the cold viruses. Also, there's less need for a cold vaccine. Colds are minor infections of the throat, nose, and sinuses. Colds generally come and go with no serious complications. You're miserable for a few days, then it's over.