Pertussis continues to put New Zealand's immunisation strategy to the test

Young children in New Zealand remain at an unacceptably high risk of pertussis. As an indicator of child disease burden hospitalisation rates have increased in each decade since the 1960s. Despite improvements over the past 15 years immunisation coverage (77% at age 2 years in 2005) remains lower than the level of about 95% necessary to control pertussis. For global pertussis control, seven strategies beyond the primary infant series and early childhood booster doses are currently recommended: (1) Reinforce and/or improve infant and toddler immunisation strategies; (2) Universal preschool booster doses; (3) Universal adolescent immunisation; (4) Universal adult immunisation; (5) Selective immunisation of new mothers, family, and close contacts of newborns; (6) Selective immunisation of healthcare workers; and (7) Selective immunisation of childcare workers. The first of these--reinforcement and/or improvement of current infant and toddler immunisation strategies--is the highest priority for New Zealand and would reduce infant pertussis disease burden. The universal preschool booster (age 4 years) and the adolescent (11 year) booster should remain. Because of low coverage and unknown effectiveness for protection of infants routine adult pertussis immunisation is of lower priority. Of the targeted strategies selective immunisation of healthcare workers is necessary to prevent nosocomial spread to vulnerable infants. All staff who work in neonatal units and other clinical settings where there are infants should receive a booster dose of pertussis vaccine. Control of pertussis in New Zealand continues to prove elusive. Improving immunisation coverage and timeliness should remain the primary focus of pertussis control in New Zealand.