A cost-minimisation analysis: comparison of acellular versus whole-cell hexavalent paediatric vaccination strategies in Argentina

Background: Argentina’s National Immunization Program currently administers a pentavalent whole‑cell pertussis (wP) vaccine (diphtheria, tetanus, pertussis, hepatitis B, and Haemophilus influenzae type b) alongside inactivated poliovirus vaccine (IPV) during infancy. Hexavalent vaccines, with IPV incorporated into the formulation, combining protection against six diseases (diphtheria, tetanus, pertussis, hepatitis B, Haemophilus influenzae type b, and poliomyelitis) in a single injection, and are available either wP or acellular pertussis (aP) antigens. By consolidating two injections into one, hexavalent formulations could streamline delivery, reduce the number of injections infants receive, and improve tolerability and compliance. To inform potential schedule modifications, this cost-minimisation analysis compared the societal costs of implementing wP or aP hexavalent vaccination schemes in Argentina. Methods: This was a cost-minimization analysis conducted from a societal perspective, comparing wP and aP hexavalent vaccination schemes in Argentina. The study population comprised infants born in Argentina between 2021and 2023, stratified by healthcare market, gestational age, and birth weight. Costs included direct medical costs, parental costs, and the cost of vaccine acquisition and administration. Total vaccine-related costs were disaggregated into vaccine acquisition, programmatic costs, and adverse event (AE) management costs for each scheme. All costs were presented in 2025 US dollars. Results: Total societal costs were lower for the aP hexavalent scheme ($84.9M) compared with the wP hexavalent scheme ($93.2M), yielding savings of $8.3M (8.9%). Although vaccine acquisition costs were $24.5M higher for the aP scheme, these were offset by a $32.8M (54.6%) reduction in AE management costs. In the public sector, which accounts for 94% of administered doses, the aP scheme reduced total costs by $9.1M. Premature infants experienced the largest proportional reductions in AE‑related costs. Sensitivity analyses confirmed the robustness of findings, with greater savings observed under higher coverage assumptions and when applying higher AE rates. Conclusion: This analysis demonstrates that the aP hexavalent scheme is associated with lower overall societal costs than the wP hexavalent scheme in Argentina.