Presentation (CTI)

OBJECTIVES: To evaluate the distributive and equity impact of switching from a hexavalent whole cell pertussis containing vaccine (Hexa.wP) to an acellular hexavalent vaccine (Hexa.aP) in country, by estimating the financial effect generated through the reduction of adverse event related expenditures and their distribution across households by income level.
METHODS: An equity analysis was conducted from the household perspective based on a prior cost minimization analysis. Reductions in expenditures related to medication, transportation, and caregiver productivity losses attributable to the lower reactogenicity of the Hexa.aP vaccine were estimated. Household income and composition data were obtained from the 2024 National Household Survey. Households were stratified by per capita income deciles. Equity was assessed using two complementary approaches: effective benefit (avoided expenditure as a proportion of per capita income) and concentration analysis of total benefits by socioeconomic level. Sensitivity analyses were performed using alternative adverse event frequency scenarios.
RESULTS: Switching to Hex.aP reduced adverse event related costs by USD 15.9 million, corresponding to average savings of USD 13.2 per vaccinated child. Relative benefit showed a marked distributive gradient, representing 13.2% of per capita income in the lowest income decile compared with 0.8% in the highest decile, indicating an effect magnitude 17 times greater among lower income households. Concentration analysis showed that the lowest income decile captured 27% of total benefits, the lowest quintile 45%, and the three lowest deciles 58%. The concentration curve lay above the line of equality, confirming a progressive distribution pattern. Sensitivity analyses maintained the direction of the findings and showed even greater distributive benefits under scenarios with higher adverse event frequencies.
CONCLUSIONS: Replacing Hexa.wP vaccines with Hexa.aP generates progressive financial protection, with proportionally greater benefits accruing to lower income households. Incorporating social equity considerations into vaccine economic evaluations captures value dimensions not reflected in traditional analyses based on vaccines costs.