Proposal of a Vaccination Needs Index to Prioritise Municipal Interventions in Brazil

Addressing population health needs requires integrating indicators expressed on non-comparable scales, particularly for vaccination, a cornerstone of public health.

To propose and implement a Vaccination Needs Index based on national administrative data on tracer vaccines for children to support the prioritisation of Brazilian municipalities.

In this ecological study, we developed and applied a Vaccination Needs Index using national administrative data from 5570 Brazilian municipalities (2018-2022), integrating transformed and standardised indicators of vaccination coverage and the number of susceptible children for three tracer vaccines: diphtheria, tetanus, and polio (DTP) (third dose), polio (third dose), and measles, mumps, and rubella (MMR) (second dose).

The estimated national coverages achieved in 2022 for the analysed vaccine doses were 79% for DTP, 67.7% for polio, and 46.1% for MMR. Consequently, approximately 3.0, 4.8 and 7.9 million children remained unvaccinated for these vaccines, respectively. When compared with criteria prioritising either unvaccinated children or low coverage alone, the top 5% of municipalities (n = 278) with the highest Vaccination Needs Index scores included a balanced mix of large, medium and small populations, with greater representation of the Legal Amazon region and Special Sanitary Indigenous Districts. These municipalities also had higher income inequality than the others, showing a mean difference in the Gini coefficient of 4.9 percentage points (95% CI: 4.2-5.7).

The Vaccination Needs Index effectively integrated absolute and relative vaccination indicators, identifying populations with intersecting vulnerabilities and socioeconomic inequities. It provides a practical and scalable tool to guide tailored interventions and optimise resource allocation, thereby preventing the resurgence of vaccine-preventable diseases.