There is a great deal of misunderstanding by patients and even doctors about shingles. People often believe it is caught from someone with chicken pox, or that it can cause shingles in another person. Education is the key to eliminating these myths. Shingles is the blistering rash in a sensory dermatome that is caused by a reactivation of the varicella zoster virus from the sensory ganglia (the junction between the sensory peripheral and central nervous systems). To develop shingles, the person must have had a prior chicken pox infection (whether this was clinically obvious or not) as chicken pox is caused by the same virus.
It therefore follows that people with shingles are already immune to chicken pox, and anyone who knows they have had chicken pox or shingles cannot catch shingles from the person who has it. If someone has never had chicken pox or shingles, they may not have immunity to the varicella zoster virus (this is not definite unless confirmed by IgG immunity for varicella zoster, as some people do not know they have had chicken pox when very young). If non-immune, these people can catch chicken pox, not shingles, from direct physical contact with the shingles rash or its secretions. They cannot catch chicken pox from that person coughing on them or sitting near them.
It is extremely important to explain this to patients, as people (especially adults) who do not know if they have definitely had chicken pox, or vaccination for chicken pox, require testing for immunity, and vaccination if non-immune. Chicken pox is generally more severe in adults, who have a higher risk of developing varicella pneumonia. When a patient is diagnosed with shingles, they should also be asked about the possibility of non-immune relatives who need vaccination, and advised against close contact with them until after the rash has gone.