Can the varicella vaccine cause shingles?
Yes, but this happens much less often among people who have been immunized than among those who were naturally infected with the chickenpox. Shingles is a rash with painful blisters that occurs in some people who previously had chickenpox. This is because after a person is exposed to the varicella virus, it can continue to live silently for many years in that individual’s nerve cells. Later in life, the virus can become reactivated, moving from nerve cells to the skin, causing the painful condition as the virus multiplies. Shingles is less common among people exposed to varicella virus through the vaccine. About 0.2% of the people who had chickenpox earlier in life (20 cases per 10,000 people who had chickenpox) will develop shingles each year. Only 0.003% of people (.03 cases per 10,000 doses, or 3 cases per million doses) who have been given the varicella vaccine have developed shingles. When it develops, shingles in vaccine recipients is much milder than in people who had chickenpox
