What is Chickenpox?

Chickenpox is a common, highly contagious childhood illness caused by the varicella-zoster virus. It causes an itchy rash that starts as small red spots, develops into fluid-filled blisters, and then crusts over, usually appearing in waves over several days, often alongside a mild fever.

Most children recover fully within one to two weeks with simple care at home. It spreads very easily through the air and through contact with the blisters, so children are usually kept away from school or childcare until all spots have crusted over.

Chickenpox is usually mild in children but can be more serious in adults, and especially so during pregnancy — for both the pregnant person and the baby. Most adults have already had chickenpox and are immune, but anyone who hasn't had it before and is exposed during pregnancy should contact their maternity team promptly. Infection in early pregnancy carries a small risk of affecting the baby's development, while infection close to delivery can risk the baby developing a serious infection shortly after birth — a simple blood test can check immunity if there's any doubt.