Chickenpox is a very infectious illness caused by a virus called herpes zoster (part of the herpes family). The medical name for chickenpox is varicella. Most people in the UK get chickenpox in childhood, when it is a mild infection causing a rash. Once you have had chickenpox, you cannot catch it a second time. This is called being immune to it (your body produces antibodies, which are the body's defence system against infection). Nine out of ten pregnant women (90%) in the UK are immune to chickenpox. If you are infected for the first time as an adult, it tends to be more serious.
If you grew up in a tropical or subtropical area, you are less likely to have had chickenpox in childhood. If you subsequently move to the UK, you have a greater risk of catching chickenpox than women who were born and grew up in the UK. Your doctor or midwife may discuss testing your immunity while you are pregnant.
The leaflet can be downloaded as a pdf by clicking on the link below.