What is chickenpox and how do you get it?

Every year in New Zealand there are many of cases of chickenpox - around 50,000.1 Although the disease is mild for most children, about 150–200 cases end up in hospital with severe complications such as bacterial skin infections, brain inflammation (meningitis and encephalitis) and nerve damage. (1,2) Most severe cases occur in children who were otherwise healthy.(1)

The chickenpox (varicella) virus is very easy to catch and is usually spread by droplets in the air when an infected person coughs or sneezes.(1,3) This means that anyone in your family who is exposed to chickenpox and hasn't had it before is likely to get sick.(4) It takes between 10-21 days before symptoms show, so often brothers and sisters will get sick one after the other. (1) The infection usually starts with a fever, then a rash appears that turns to blisters and spreads to different parts of the body in waves. (2,3) On average children have about 200-400 blisters, which sometimes leave scars. (2) The virus can be spread from 1 or 2 days before the rash emerges until the last rash dries up, about 1-2 weeks later. (1,2)

How do you treat chickenpox?

Infected children are advised to be kept at home and out of daycare or school until all rash lesions have crusted. (1) Sometimes a soothing lotion such as calamine lotion can help with the itching of the blisters. (4) Give paracetamol for fever or pain.(1,4) Do not give aspirin to children with chickenpox as this might increase the risk of a rare severe condition called Reye's Syndrome. (1,4)

How do you prevent chickenpox?

Prevention of infection by vaccination is the most effective way to prevent the serious effects of chickenpox . (3-6) One dose of the vaccine is about 80-85% effective at preventing all chickenpox and two doses are about 92-97% effective. (2,5)


The benefits of choosing to vaccinate means your child will:

  • avoid hospitalisation and severe disease (1,5)
  • avoid long term scarring of the body from chickenpox blisters (2)
  • avoid suffering itching, blisters and discomfort (2,4)

Immunity lasts for at least 20 years, which is as long as vaccinated people have been followed. (6) If a vaccinated child does get chickenpox, the illness is much milder. (2) The chickenpox vaccine is generally well tolerated, with most side effects occurring around the injection site; for example, soreness and redness. (5)

In New Zealand, the chickenpox vaccine is recommended for children, but is not funded. (1) The vaccine is available for purchase through your family doctors. Talk to your doctor or nurse to see if the vaccine is right for your child.

For more information contact the Immunisation Advisory Centre on 0800 IMMUNE or visit www.immune.org.nz.

References
1. Ministry of Health; Immunisation Handbook 2011, Wellington: Ministry of Health; 2011.
2. Heininger U, Seward JF. Lancet 2006 14;368:1365–76.
3. Walls T, Wilson E. NZMJ 2010;123:22-5.
4. Kidshealth Chickenpox. Available at: www.kidshealth.org.nz/index.php/ps_pagename/contentpage/pi_id/194 Accessed 6th June 2012.
5. Varilrix® Data Sheet, GSK New Zealand. July 2011.
6. Takahashi M. Paediatr Drugs. 2001;3:285–92

Vaccinations