The blisters (vesicles) that develop as a result of shingles contain virus particles. The virus can be spread through direct contact with open blisters. A person who has shingles is contagious until the last blister has scabbed over.
If you have not had chickenpox before (usually young children), you can catch it from someone with shingles. However, you cannot catch shingles from someone with shingles because the virus has to be reactivated, rather than passed on. If you have had chickenpox in the past, you are immune and cannot get it again.
Pregnant women
Shingles during pregnancy can be serious. Therefore, if you are pregnant and have not had chickenpox, you should avoid contact with someone who has shingles. If you are pregnant and get shingles, your risk of getting pneumonia is increased. There is also a slight risk that if your unborn child is exposed to the herpes varicella-zoster virus, s/he may be damaged or miscarried. However, this is less likely with shingles than chickenpox.
Weak immune system
If you have a weak immune system, it is best to avoid close contact with someone with shingles. If you have a shingles rash, you should avoid sharing towels, going swimming, or playing contact sports, in order to avoid passing the virus on to someone who has not had chickenpox.
