In general, the body’s immunity does not increase after a cold has healed itself. There are many types of viruses that cause colds. Antibodies induced by the first infected virus do not neutralize other viruses; they exist for a short period of time; and viruses mutate quickly, causing the previously induced antibodies to lose their protective effect. 1. Common viruses that cause colds include: rhinovirus, adenovirus, respiratory syncytial virus, influenza virus, parainfluenza virus, and coxsackievirus. If a cold is caused by rhinovirus, adenovirus, or both, it will not be resistant to the other viruses even after it is cured. 2. After a cold is cured, the antibody induced by the virus exists in the body for a short period of time, and even if the same virus is interrupted for a period of time, there is still a possibility of being infected by the same virus again and causing a cold. In addition, viruses mutate quickly, which makes the antibodies ineffective in case of reinfection. However, under special circumstances, the body’s immunity may be strengthened after self-healing, such as during early childhood, when the immune function is perfected, and the immune function may be strengthened after a cold, but it does not happen absolutely.