Systematic review of cost projections of new vaccine introduction

A recent review of guidance documents on vaccine delivery costing revealed current guidance on cost projections for new vaccine introduction has gaps on methods of sampling, data collection and analysis. In preparation for updating the respective guidance, this systematic review was undertaken to qualitatively assess methodologies used in new vaccine cost projection studies. This will inform researchers and stakeholders about the methods of new vaccine introduction cost projections for strategic directions in countries where cost data are not available.

We systematically searched four search engines (PubMed, Cochrane Open Access, Mendeley and Google Scholar) for articles on cost projections for new vaccines published between 1999 and 15 June 2022. We developed inclusion and exclusion criteria for the selection of articles and analyzed the results using a PRISMA 2020 flow diagram.

Out of 1,108 articles identified, 171 met the criteria for inclusion in the study. Half of the articles were from high-income countries (50%), and most cost projections were part of cost-effectiveness analysis (84%). The most common source of cost data was secondary national information (43%), followed by author's assumptions (17%), secondary international information (14%), and primary data collection (7%). 19% of studies didn't include costs to deliver vaccines in their cost estimation. Among studies that included secondary vaccine delivery costs, approximately half only calculated vaccine administration costs (50%), while 35% included incremental system costs and 15% utilized ingredients data. Two thirds of the studies were conducted to inform policymakers of the cost-effectiveness or cost-benefit of introducing the vaccine.

Half of the economic evaluations on new vaccine introductions only included partial vaccine delivery costs. Thus, total costs of vaccine introduction were often being underestimated in economic evaluations. This suggests that guidelines on economic evaluations and journals should recommend that authors include more extensive vaccine delivery costs in their studies.