Reactivation of the varicella-zoster virus that remains dormant after a prior chickenpox infection
Direct spread is not how shingles is usually contracted; you must already have had chickenpox or the varicella vaccine
Exposure to someone with active shingles can transmit varicella-zoster virus to a person who has never had chickenpox or the vaccine
Contact with fluid from shingles blisters can spread the virus
Breathing in virus particles from blister fluid is less common but possible with close contact
Risk is higher with close, prolonged contact with an infected person
Risk is higher if you are unvaccinated or immunocompromised