INTRODUCTION: Outreach Immunisation Services (OIS) enable children who have not been immunised on time at general practice to be immunised in the community, thereby improving immunisation coverage and reducing equity gaps.

AIM: To identify the most effective service delivery models and make recommendations for more effective and cost-efficient OIS delivery in New Zealand.

METHODS: Data collection and thematic analysis through a detailed review of OIS contracts and service specifications, an online survey and in-depth interviews with stakeholders and providers, and an analysis of cost data was conducted.

RESULTS: In total, 28 OIS providers completed survey questionnaires, 28 OIS staff were interviewed, and cost effectiveness data were obtained from 11 providers. The surveys and interviews identified key themes around identifying clients with the highest needs, effective engagement strategies, staffing requirements, and service challenges. On average, each OIS referral costs NZ$361 (median NZ$257), and each vaccination event costs NZ$636, ranging from NZ$145 to NZ$2403. Characteristics for two separate models of service delivery were identified based on provider size.

CONCLUSION: There is considerable range in costs and style of OIS delivery, and efficiencies can be gained. Models need to fit with locality needs and include adequate resourcing, staff with good local knowledge, close relationships with other key child health services and preferably co-location, sustainable funding, and regular service reviews. OIS are part of an effective integrated service that relies on accurate data, positive relationships and a rapid response when children fail to present for vaccination in a timely fashion.