Children's health specialists want universal chickenpox vaccine added to the list of state-funded immunisations, after their study showed that admission to hospital with the viral illness is not uncommon.
Chickenpox vaccination is state-funded in Australia, but in New Zealand the Government pays for it only for children and adults at high risk of certain diseases due to other medical conditions.
Most New Zealand children catch chickenpox, also called varicella, and have mild symptoms. It causes itchy blisters all over the body which children can't keep from scratching. The scratching can lead to bacterial skin infections and this is the leading reason for chickenpox cases landing in hospital.
Health authorities warn against the parental practice of holding "chickenpox parties" to deliberately infect their children, because of the risk of severe complications and even death.
"The perception of varicella always being a benign childhood disease needs to be redressed, with almost 10 per cent of cases hospitalised with varicella requiring intensive care unit admission in this study," say the researchers, mainly paediatricians from Starship children's hospital and the Auckland and Otago Universities.
They found that 144 children were admitted to a hospital with chickenpox in the two years to November 2013. Their median age was 2.4 years and Maori and Pacific Island children were around three times more likely than European children to be admitted to hospital with the illness.
Of those admitted, 75 per cent had an infection, 11 per cent had a respiratory disorder and 11 per cent had neurological symptoms.
"Cases that require ICU admission are more likely to have ongoing problems upon discharge, as shown in our review where almost one-third [of] cases have permanent disability," the researchers say in the Journal of Paediatrics and Child Health.
"There were no reported deaths; however, 19 per cent had ongoing problems at discharge."
They say their study "gives support for the inclusion of universal varicella vaccine".
"Cost-effectiveness modelling of a funded universal varicella vaccination programme -- single dose -- in New Zealand suggested a return of $2.79 for every dollar spent on the programme."
Auckland GP Dr John Cameron said many considered chickenpox a normal part of growing up.
"Parents think, 'We all had it, so the kids will have it as well'."
"It's now a preventable disease and people need to be aware of the dangers associated with chickenpox infection."
"It makes kids utterly miserable and it can lead to hospitalisation, as this research shows."
Having the jab at his Westmere clinic costs $75.
Waikato immunisation facilitator Helen Ride said the illness could impose a financial burden on families.
"Even in a mild case, the child will be excluded from day-care or school and will require a parent to stay home and care for the child. If a number of children in the household are susceptible to chickenpox then this can equate to over four weeks home caring for infected children."
The Immunisation Advisory Centre at Auckland University has been calling for the Government to fund a chickenpox vaccine for at least a decade.
Common side-effects of chickenpox vaccine are listed as including soreness at the injection site. Uncommon side-effects include shingles later in life, and rare/very rare side-effects include severe allergic reaction.