Can you still get chickenpox after vaccination?

Vaccination trains the immune system to recognise varicella, the virus that causes chickenpox. Protection is strong but not an absolute barrier, so a vaccinated person may occasionally develop an itchy rash, fever, or scattered blisters after exposure. Compared with illness in someone who has not been vaccinated, symptoms may be less extensive or shorter-lived. A rash can also have causes other than chickenpox, so appearance alone cannot confirm the diagnosis. Chickenpox can later remain dormant in the body and reactivate as shingles; these are related conditions but are not the same illness.

Contact a GP for advice if you develop a new blistering rash after exposure or vaccination. Mention when the rash began, whether you have had one or more vaccine doses, and whether anyone at home is pregnant, a newborn, or immunocompromised. Until you receive advice, avoid close contact with people who may be vulnerable and do not share towels or clothing. Keep the skin clean, avoid scratching, and ask before using medicines. A clinician may discuss antiviral treatment for selected people and antihistamine treatment for troublesome itching.

Seek urgent medical advice for breathing difficulty, severe drowsiness, confusion, dehydration, a rapidly worsening rash, or skin that becomes hot, very painful, or pus-filled. Contact a clinician promptly for fever with blisters if you are pregnant, have a weakened immune system, or are caring for a very young infant. These situations can change which treatments are suitable and how quickly assessment is needed.

Ask whether the rash fits chickenpox, whether testing is useful, how long to avoid close contact, and whether your vaccine record suggests another dose or a different preventive plan.