Shingles (also known as herpes zoster) is a painful viral infection of the nerves that results in a rash, often contained to just one side of the body. It's caused by the reactivation of the virus that causes chickenpox.
Any person who has had chickenpox may develop shingles later in life. After a person recovers from chickenpox, the varicella-zoster virus remains dormant in the nerve roots. In certain people, the virus reactivates when the immune system becomes weakened due to stress, age or disease. Approximately half of all people who live to be older than 80 will develop shingles, according to the U.S. Centers for Disease Control and Prevention.
Is Shingles Contagious?
Chickenpox is the reaction to an initial infection with the virus; shingles is simply the reactivation of that virus many years later. Therefore, a person with shingles can pass the varicella-zoster virus only to another person who has never had chickenpox. Though the virus can be transmitted to the non-immune person, that person won't contract shingles--but may contract chickenpox.
How Can the Virus Be Transmitted?
The transmission can occur through contact with the open sores of the shingles rash. One study reported in the Journal of Infectious Diseases found that the virus could become airborne from exposed shingles sores.
Communicability of the Varicella-Zoster Virus
The varicella-zoster virus causes chickenpox and shingles, but chickenpox is more highly contagious. Approximately 90 percent of people exposed to the varicella-zoster virus in the form of chickenpox can become infected, according to the Maryland Department of Health and Mental Hygiene. The individual is no longer infectious after the lesions have crusted over.