Maori & Pacific Island Children Overrepresented in Paediatric Intensive Care Unit (PICU) Due to Chickenpox - Study

Maori and Pacific Island children are over represented in admissions to paediatric intensive care in NZ for serious chickenpox complications with an almost threefold and sixfold increase respectively.1 Furthermore, long-term disability, usually neurological damage, were suffered by 31% of the 26 children admitted to paediatric intensive care overall, according to a 10-year study review.1

The results indicate Kiwi parents need to be aware of the potential for severe chickenpox complications, particularly as we enter one of its two peak seasons – spring.2

Of the 50,000 mostly young Kiwis who contract the Varicella (chickenpox) virus each year, up to 430 are hospitalised, mainly due to severe chickenpox or bacterial superinfection of the blisters.2,3

A New Zealand study published in the Journal of Paediatrics and Child Health, investigated the most severe and sometimes-fatal complications of the common childhood infection in children who required admission to the PICU unit at Starship Children’s Hospital.1

In the study the most common reasons for admission to PICU were neurological (e.g. seizures and encephalitis), bacterial sepsis and extensive pneumonia.1 Of the 26 admissions measured over a ten year period, 31% sustained a long-term disability, most often neurological.1

The study also showed that Maori and Pacific Island children are three- and six-fold (respectively) more likely to be admitted to PICU for varicella-related complications.1 Multiple reasons may contribute to this disparity and include household crowding, economic deprivation and other environmental and genetic factors.4-6

The study also highlighted the mortality rate of those Kiwi children who died as a result of chickenpox over the past 30 years, with the disease responsible for 10 child fatalities during that time period.1

The General Manager of GlaxoSmithKline (GSK) New Zealand, Anna Stove, says due to the significant complications and high risk of secondary infection, the Ministry of Health recommends Kiwi children are vaccinated for the chickenpox virus. "Generations of New Zealanders have been deliberately exposed to chickenpox in the past by parents seeking to ensure their child contracted the disease at an early stage in their development through attending chickenpox parties. What many parents are not aware of is that there is a risk of secondary infection and that the disease is preventable."

GSK are makers of the Varilrix® chickenpox vaccine, first licensed for use in 1994 and currently approved for use in 96 countries including New Zealand, Australia, the United States and Germany.7-10

Stove says the chickenpox vaccine has been shown to provide at least 20 years of protection, as that is the length of time vaccinated people have been followed.8

She says in countries like New Zealand, chickenpox commonly circulates in the community and a person's immunity is likely to be continually boosted, providing long-term protection after vaccination.

For more information on immunisation in New Zealand visit www.moh.govt.nz/immunisation

References

Wen et al. J Paediatric and Child Health. 2014; 50:280-285
Ministry of Health; Immunisation Handbook 2014. Wellington: Ministry of Health; 2014
Tobias et al. NZ Med J. 1998; 111:274-81
Grant et al. J Paediatric and Child Health. 1998; 34:355-9
Jefferies C et al. NZ Med J.1999; 112: 115-117
Abbott W et al. NZ Med J. 1999; 112: 243-5
GSK Varilrix® data on file
Siedler, A. and U. Arndt. Euro Surveillance. Available at: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19530. Accessed 24 September 2014 
Davis, M.M. et al. Pediatrics. 2004; 114: 786-92
Carville K.S. et al. Vaccine. 2010; 28: 2532-8