OBJECTIVES: In 1993, a single-dose 23-valent pneumococcal polysaccharide vaccine(PPSV23) was introduced in the national immunization program(NIP) in Mexico as part of older adult schedule. In 2022, PPSV23 was switched to PCV13 without a previous cost-effectiveness evaluation. This study aimed to assess the cost-effectiveness of PPSV23 vaccination compared with PCV13 for adults aged ≥65 years from the Mexican public health system perspective.

METHODS: A Markov model was used to follow a Mexico-based cohort of adults aged ≥65 years. The model has: a 1-year cycle length, a 10-year time horizon, and discounted outcomes and costs at an annual rate of 5%, assumption of 60% vaccination coverage rate. Health states included: no disease, invasive pneumococcal disease(IPD), non-bacteremic pneumococcal pneumonia(NBPP), post-meningitis sequelae(PMS), and death. Epidemiological parameters were estimated using Mexican-specific data sources; where not available, international literature was used. The population was categorized in low-risk(51%), high-risk immunocompetent(44%), and high-risk immunosuppressed(5%) for pneumococcal disease. Based on local IPD surveillance, PPSV23 and PCV13 cover 60% and 26% of serotypes causing disease, respectively. Costs were calculated in local currency and converted to US dollars using May 30, 2022 exchange rate (1US$=MXN 19.5). By WHO criteria, a highly cost-effective strategy in Mexico is US$8,329 (<1x GDP/capita).

RESULTS: For a vaccinated cohort of 10.5 million persons aged ≥65 years followed over a 10-year horizon, PPSV23 vaccination was projected to avert 4,663 additional pneumococcal cases (643 IPD including 61 meningitis cases/19 PMS/4020 NBPP) and 493 deaths (285 IPD/208 NBPP) compared with PCV13. PPSV23 dominated PCV13 with cost savings of US$ 11.2 million (reduction in direct medical costs of US$16.2 million). A local sensitivity analysis using lifetime horizon did not change the PPSV23 dominance over PCV13.

CONCLUSIONS: Under model assumptions, PPSV23 is a dominant strategy (cost-saving) over PCV13 in adults aged ≥65 years in Mexico, leading to fewer pneumococcal cases, complications, and deaths.