Vaccine 17 (1999) 5115–5117

Abstract

In uenza surveillance is a key public health activity in New Zealand. Disease surveillance assists with the development of strategies to control in uenza, while virological surveillance provides viral strains needed for the WHO network for the maintenance of current in uenza vaccines. Year-round virological surveillance is conducted by sampling hospital in-patients during routine diagnostic virology carried out by ®ve laboratories in each major population area. An enhanced national surveillance programme, similar to that recommended by the WHO, is undertaken during the winter in uenza season, May to September. Approximately 80 sentinel general practices distributed on the basis of population density throughout the country's health regions are enrolled by each region's public health unit. Each practice participates by recording the daily number of consultations that ®t a case de®nition for in uenza-like illness, and the age group of each of these suspected cases. The standardized case de®nition is: `Acute upper respiratory tract infection characterized by an abrupt onset and two of the following: fever, chills, headache and myalgia'. The data are collected weekly, collated, expressed as a rate (per 100,000) and distributed nationally to participating practices, laboratories and public health units. Sentinel practices also provide respiratory samples from three patients per week, which are forwarded to one of the ®ve regional laboratories for viral isolation and strain identi®cation. A key strategy for maintaining sentinel practice participation is the provision of virology results, on the same day.