Chickenpox is an acute, generalised viral disease resulting from a primary infection with varicella-zoster virus.

Symptoms include:

• mild fever
• malaise
• characteristic itchy vesicular rash

Chickenpox is usually not a serious infection.

A small number of individuals may experience complications including pneumonia, secondary bacterial infection and encephalitis.

The risk of severe disease is highest in:

• pregnant women
• immunocompromised individuals
• exposed newborns

After primary infection, the varicella-zoster virus will become dormant but can re-activate, usually in later life, as herpes zoster (shingles). This often occurs when the immune system is weakened.

Read more about chickenpox symptoms, transmission and treatment on NHS inform (external website).

A Streptococcus (iGAS) disease

Evidence suggests that chickenpox (varicella) is an important risk factor for invasive group A Streptococcus (iGAS) disease in children.

Health protection management guidance is available for Scarlet fever and managing outbreaks in schools and nurseries (external website).