1988 New Zealand national immunisation survey: methodology

In 1985 the Department of Health carried out a survey using a two stage stratified random sampling technique to select approximately 3000 children (made up of equal numbers of 5, 10 and 15 year olds). The principal aim was to provide a random sample of sera which could be used or stored for the future to evaluate the national immunisation programme and for screening of an ethical nature. The sampling frame was the 1983 list of public and private schools as provided by the Department of Education. Ninety primary schools and 50 secondary schools were identified, from which 3688 children were asked to participate. There was a 79% consent response rate. The survey largely succeeded in its objective of providing a nationally representative group of children, although the response rate was lower in 5 year olds (74%), in Pacific Islanders (67%), in children from upper socioeconomic status groups (75%), and in children who were reported not to have been immunised (56%). A similar survey is recommended every five years. In the mean time, laboratory analysis of the collected serum samples continues and results will be published separately.