Designing medicines that kill viruses without harming human cells is difficult. No medicine yet exists that can cure infection from cold viruses. Fortunately, your body's immune system mounts a specific response to whatever cold virus you have. It usually clears the infection within 7 to 14 days. Attempts to develop a cold vaccine have been unsuccessful because there are too many strains of cold virus and immunity is not permanent.
Most people get several colds a year.
Colds are common because so many different viruses cause them and because they are so contagious. You can also catch the same virus strain more than once. You can't completely avoid catching colds, but you can reduce the chances. Most colds are spread when virus contacts the mucus membranes of your eyes, nose or mouth. Virus is shed via the mucus of infected people.