According to Dr. Vinay Aggarwal, Internal Medicine Physician, cedars Sinai Hospital, Los Angeles, there is no major difference between a common cold and flu. The starting point of both the infection is more or less same. Sometimes common cold acts as a precursor for flu. Flu is little bit stronger than the common cold. Common cold has symptoms such as fever, cough, running nose and chills, but lacks other symptoms such as muscle ache and vomiting. The symptoms of swine flu are very much similar to normal flu. It is just the more infectious form of normal flu. People having AIDs or undergoing chemotherapy are prone to develop swine flu.