On the surface, the two diseases are not related. Chickenpox occurs in children between the ages of 3 and 9 years old and has no neuralgia; shingles is mostly seen in adults over 40 years old and has severe pain. The rash pattern and distribution characteristics of the two are also different. However, they are two successive pathogenic processes caused by the same virus that infects the body. Herpes zoster is not caused by the virus outside the body, but only by the recurrence of the virus latent in the body. The specific process is as follows: the virus first infected the body proliferates in the body, forming a viraemia that spreads throughout the body, leading to the occurrence of chickenpox. The virus can remain latent in the posterior root ganglion of the spinal cord or in the sensory ganglion of the cranial nerve until adulthood, when the latent virus is activated due to a decrease in immunity and stimulation by physical and chemical factors, causing inflammation and necrosis of the invaded ganglion, resulting in neuralgia. At the same time, the reactivated virus can proliferate along the nerve axon to the skin cells innervated by the nerve, so that a string of herpes in the skin area innervated by the ganglion appears, so called herpes zoster. Here are a few points to clarify: 1. Most people are infected with varicella zoster virus during childhood, but only some of them have clinical manifestations of chickenpox, and many others are infected without symptoms or have very mild symptoms and are ignored; 2. The body develops lasting immunity after the initial infection and rarely suffers from chickenpox again, but the specific immunity cannot clear the latent virus in the ganglion, so it cannot prevent the occurrence of herpes zoster; 3. The occurrence of herpes zoster is due to a decrease in the body’s immunity, which is triggered by many factors, such as colds, overwork, certain infectious diseases, malignant tumors, AIDS, systemic lupus erythematosus, radiation therapy, burns, and the use of certain drugs (such as immunosuppressive agents and adrenocorticotropic hormones, antimony, and arsenic). As can be seen, a person can have chickenpox or shingles successively during his or her lifetime, or only one of them can occur, or there can be no manifestation of the virus despite the infection. Theoretically, there is a virus in the blister fluid of a person with herpes zoster, and children who are not immune to this virus can be infected with chickenpox if they come in contact with the blister fluid, but the chance of this happening is relatively small. Adults are mostly immune, so they will not develop the disease even if they are exposed to it. Therefore, herpes zoster does not cause an epidemic in the population. Patients with shingles also do not require special isolation, but close contact with children should be avoided.