Chickenpox parties are a safe way to build immunity

What the research found

Australian guidance says most people with chickenpox have mild symptoms, but it can be severe. Complications include bacterial infection of the blisters and scarring. Very rarely, it causes pneumonitis (lung inflammation) or encephalitis (brain inflammation). Experts writing in 2025 said one in every 100 people has infection-related complications, and there is no way of predicting who.

A recent chickenpox infection also substantially increases the risk of serious bacterial infection, such as invasive group A strep. Children's hospital guidance lists group A strep and golden staph as key complications. Infected children can also pass the virus on to pregnant women, newborns and people with weak immune systems, who can become very sick.

Australian experts advise avoiding chickenpox parties because a safe and effective vaccine exists. Cochrane reviews (2020 and 2021) covered vaccines including the chickenpox vaccine and describe the diseases as serious. A 2020 systematic review of vaccine safety found vaccines have an excellent safety profile overall. Since the vaccine began in 2005, hospitalisations have fallen. Two doses give about 95% protection.

What it doesn’t mean

• Most children who catch chickenpox recover well. The point is that the risk is unpredictable and avoidable, not that every case is serious.
• Children who have had chickenpox can still safely have the vaccine. Vaccination should not be given to pregnant people or people with weakened immune systems, so talk to a GP first if that applies to your family.
• If a pregnant person, newborn or immunocompromised person has been near someone with chickenpox or shingles, they should see a health professional straight away. Talk to a GP or child health nurse about the vaccine schedule and the unfunded second dose.