Criteria for vaccine introduction: results of a DELPHI discussion among international immunisation experts on a stepwise decision-making procedure

Based on a model of a stepwise approach for decision-making on vaccine introduction, this study aimed to reveal unpublished decision aids, to assess cut-off limits or thresholds for vaccine introduction that have already been used, and to discuss the comprehensiveness and feasibility of our suggested model.

Forty international immunisation experts were invited to a DELPHI discussion, 14 finally participated. Experts received a questionnaire and were asked for comments on other experts’ opinions and specification of their previously given answers in the second DELPHI round. We did not intend to develop a consensus document.

Though most of the DELPHI participants were not aware of decision aids other than the five that had been used for the development of our model, the international discussion revealed four additional national documents that define decision-making criteria. Except for one example with a cost-utility ratio, no defined thresholds or cut-off limits have been used in vaccine introduction decisions so far. The majority of experts believe that a stepwise approach could enhance the feasibility of decision aids. The experts agreed that the influence of each single criterion of our model should be at least “important” for decision-making. The most often mentioned possible negative consequence that could arise from a rigid stepwise procedure, was a delay of the vaccine introduction process.

The suggested stepwise procedure provides a systematic and evidence-based standardised way to support public health immunisation policy decisions. A framework could be a common starting point.