Cold and Cough are common because some of the causative viruses do not produce lasting immunity after infection and some viruses have numerous serotypes . Cold viruses that do not produce lasting immunity include respiratory syncytial virus (RSV), parainfluenza viruses (PIVs), and human coronaviruses (HCoVs). Cold viruses that have numerous serotypes but produce lasting serotype-specific immunity after infection include rhinoviruses, adenoviruses, influenza viruses, and enteroviruses.