Maternal Tdap immunisation projected cost-effective for infants in Sabah, Malaysia

Maternal Tdap immunisation could substantially reduce infant pertussis in Sabah, Malaysia, at a cost-effectiveness ratio of RM32,291.39 per discounted life-year gained, according to a cohort-based economic evaluation of the 2018 birth cohort published in Cost Effectiveness and Resource Allocation. The study modelled a single maternal Tdap dose against the tetanus toxoid-containing maternal vaccination practice actually used in Sabah in 2018.

The analysis was conducted from the Ministry of Health provider perspective using a decision-tree model. Clinical and epidemiological parameters were drawn from Sabah surveillance data, while treatment costs came from 22 infant pertussis cases managed at Sabah Women and Children Hospital. The model followed 53,025 live births for pertussis outcomes during the first year of life and valued survival benefits over the remaining lifetime, with future life-years discounted annually at 3%.

Under these assumptions, maternal Tdap immunisation was projected to avert 59.46 infant pertussis cases and prevent 6.18 deaths in the 2018 cohort, generating 183.94 discounted life-years. The incremental provider cost was RM5,939,564.82, equivalent to RM112.01 per live birth. Dividing the incremental cost by the discounted life-years yielded the incremental cost-effectiveness ratio of RM32,291.39 per discounted life-year gained.

The result proved sensitive to several inputs. When life-years were discounted at 5% instead of 3%, the ICER rose to RM49,300.93. When the mean disease burden across the complete 2017–2019 birth cohorts was applied, the ICER increased to RM37,899.76. These scenario analyses indicate that the economic value of the programme depends materially on how much pertussis circulates locally and on the discounting convention adopted.

Probabilistic sensitivity analysis added a measure of decision uncertainty. At a scenario reference value of RM44,708 per discounted life-year, the reproducible probabilistic analysis estimated an 81.1% probability of positive net monetary benefit, meaning that under most sampled parameter combinations the programme would be considered worthwhile at that threshold.

The authors concluded that maternal Tdap immunisation was projected to produce substantial reductions in infant pertussis morbidity and mortality in Sabah, where young infants remain vulnerable before completing their primary vaccination series. Pertussis continues to cause preventable morbidity and mortality in this age group, and maternal immunisation provides passive protection during the period of vulnerability.

However, the economic value of the programme was sensitive to vaccine acquisition price, disease burden, mortality effectiveness, discounting and the reference value applied. The authors cautioned that interpretation is limited because the ATT input came from a consumer price guide, the Tdap input was an international proxy, and complete programme implementation costs were unavailable.

The findings are presented as locally relevant evidence for procurement decisions and programme sustainability in Sabah. Because the evaluation was historical, projecting outcomes for a 2018 cohort rather than measuring a newly implemented programme, the results reflect what a Tdap programme would have been expected to deliver under the conditions of that year rather than observed post-implementation performance.

One-way, scenario, threshold and probabilistic sensitivity analyses were all conducted to characterise uncertainty in the estimates. Together they frame the headline ICER not as a fixed value but as a central estimate within a range that shifts with discount rates, disease burden assumptions and vaccine pricing, underscoring the importance of local data when ministries weigh the introduction of maternal pertussis immunisation.

Subject of Research: Cost-effectiveness modelling of maternal Tdap immunisation for preventing infant pertussis in Sabah, Malaysia

Article Title: Cost-effectiveness of maternal Tdap immunisation in Sabah, Malaysia: a historical evaluation of the 2018 birth cohort

Article References: Loong, A. C. E., Ibrahim, M. Y., Ramdzan, A. R., & Wasir, R. (2026). Cost-effectiveness of maternal Tdap immunisation in Sabah, Malaysia: a historical evaluation of the 2018 birth cohort. Cost Effectiveness and Resource Allocation. https://doi.org/10.1186/s12962-026-00826-w

Image Credits: AI Generated

DOI: 10.1186/s12962-026-00826-w

Keywords: maternal Tdap immunisation, pertussis, cost-effectiveness, Sabah, Malaysia, infant vaccination, life-years gained, decision-tree model, sensitivity analysis, health economics, maternal, Tdap