If you do not catch a cold within 1-3 years, it is usually a normal situation, which proves that the body’s immunity is relatively normal, and the body’s basic physique and basic metabolic rate are relatively good conditions, which is a normal, healthy physical state at this time. Colds occur when the body is infected with bacteria, viruses, fungi or other pathogenic microorganisms due to physical exertion or weakness, as well as when the immune system is extremely low, when the body is cold, or when the body is on fire. When the body’s immunity is normal, it is normal if it does not produce a cold for 1-3 years. However, if you do not get a cold for more than 3 years or even 5-10 years, it is an abnormal phenomenon. At this time, it is a case of abnormally high immunity, which requires some immunomodulatory treatment, and you should go to the hospital for cellular immunity and humoral immunity related examination.