3.3.3. Vaccination Programs Evaluated

Intervention(s) and comparator(s) assessed in the economic evaluations were mostly between the introduction of a vaccination program vs. no vaccination (*n* = 12, 52%) [6,8–11,13,24,26,28,31,34,35]. The remaining studies were modeled to evaluate the distributional impact of improving vaccination coverage of the vaccination programs across equity-relevant subpopulations. These included the introduction of a vaccine into a routine vaccination program vs. the introduction of a vaccine into a routine vaccination program with improving vaccination coverage vs. no vaccination (*n* = 3, 14%) [23,29,30], improving vaccination coverage vs. status quo of the currently implemented vaccination program (*n* = 4, 19%) [7,12,32,33] and improving vaccination coverage vs. status quo vs. no vaccination (*n* = 2, 10%) [25,27].

Strategies to improve equitable vaccination coverage described in four studies can be categorized into two broad approaches. Firstly, strategies specifically designed to improve vaccination coverage in the more socially disadvantaged groups, including investing additional resources into rotavirus vaccine delivery in rural areas [33], providing financial incentives for those who received measles vaccine as part of routine immunization with the aim to increase vaccination coverage by 10% in the bottom two income quintiles [7], and revising the eligibility criteria of receiving pneumococcal vaccination to increase the number of eligible vaccine recipients, especially in the Black population in the US [32]. Secondly, strategies designed to achieve equal vaccination coverage across equity-relevant subpopulations, including providing supplemental doses of measles vaccine in addition to the doses prescribed in the standard vaccination schedule (i.e., supplementary immunization activities (SIAs) or mass campaigns) with the aim to achieve 90% vaccination coverage in all income quintiles [7] and providing HPV vaccine as a school-only program or implementing a new mandatory law requiring active opting-out of HPV vaccination with equal coverage across ethnicity and income tertiles [25].

Potential benefits of achieving equitable vaccination coverage were also estimated in four studies, of which two studies estimated the impact of incremental reductions in vaccine under-coverage from current to full coverage [23,29]. The other studies investigated the impact of a scenario when all equity-relevant subpopulations had the same vaccination coverage as the highest coverage subpopulation [27,30]. However, these studies did not describe how to achieve the said equitable vaccination coverage.
