Shingles does not have an incubation period, according to Mayo Clinic. The infection occurs as a result of the reactivation of a virus that is already present in the person's body. The virus, varicella zoster, is the same one that causes chicken pox.
Chicken pox is a highly contagious infection that spreads through the air, explains the U.S. Centers for Disease Control and Prevention. After exposure, the typical incubation period is 14 to 16 days. Once a person recovers from chicken pox, the virus stays in his body, "hiding" in the nerves around the spinal cord and the brain, Mayo Clinic notes. In some people, the virus becomes active again many years later, causing a blistered rash, usually only on one side of the body, and pain, which is often severe. Doctors call this infection shingles.
Unlike chicken pox, shingles only spreads through direct contact and is not contagious until the rash appears, explains MedicineNet. However, direct contact with a person who has shingles can cause chicken pox in anyone who has not been vaccinated or had the disease.