By analyzing national children vaccination coverage from spatial perspectives, the study aims to uncover insights into traditional surveillance. This will help to identify coverage rates, regions of greater vulnerability by providing a differentiated look at the logic of equity in health. Understanding the low childhood vaccination coverage will help to guide public policies for the purpose of interventions.
The study was divided into two phases. In phase one, a mixed ecological study was conducted using secondary data. Phase two involved a cross-sectional study in the Baixada Santista Metropolitan Region (RMBS), which included the administration of a questionnaire developed and validated by the researchers.
The spatial analysis of vaccination coverage is an innovative methodology that identifies clusters of regions more vulnerable to vaccine-preventable diseases. This analysis was conducted using Moran’s Global and Local autocorrelation indices. To examine the autocorrelation of these clusters, Moran and Lisa maps were utilized. The results were classified into four categories:
1. High-High: regions with high vaccination coverage that are surrounded by other areas with high coverage.
2. Low-Low: areas with low coverage that are surrounded by other regions with low coverage.
3. High-Low: regions with high coverage that are surrounded by areas with low coverage.
4. Low-High: areas with low coverage that are surrounded by regions with high coverage.
This approach can significantly enhance decision-making by identifying areas where herd immunity through vaccination is at risk.
The Virtual Platform Observatório das Vacinas (Vaccine Observatory) is the primary product of this project. It is a dynamic, interactive platform that showcases vaccination coverage for recommended vaccines for children under two years old across all 5,570 municipalities in Brazil. The platform is designed for health managers, parents, academics, and others interested in vaccination. Additionally, the spatial analysis of vaccination coverage introduces a methodological innovation by identifying areas with low and high vaccination rates throughout the country.
In recent years, Brazil has experienced a significant decline in vaccination coverage for the basic childhood immunization schedule, particularly between 2016 and 2017. This decrease jeopardizes both individual protection and herd immunity, increasing the risk of a resurgence of diseases that were previously under control or eliminated, such as measles and yellow fever. Low vaccination coverage for vaccines like HPV and the risk of poliovirus reintroduction are particularly concerning, especially in regions with significant vaccination gaps.
Several factors contribute to this decline, including changes in the information system, limited availability of vaccination services outside working hours, and the spread of misinformation about vaccines on the internet. In response to these challenges, a project was initiated to analyze childhood vaccination coverage across all 5,570 Brazilian municipalities. This project employed a spatial approach to relate vaccination coverage to various socioeconomic, environmental, and health factors. The objective was to gain a better understanding of the reasons behind the decline in vaccination rates and to propose solutions aimed at increasing adherence to vaccination programs and reversing the public health risks associated with reduced vaccination rates.
The dynamic interactive platform, Observatório das Vacinas (www.observatoriodasvacinas.com.br), plays a crucial role in disseminating knowledge and bridging the gap between academia, management, and various audiences. The project has also contributed to enhancing the PNI Information System (SI-PNI) by identifying inconsistencies and mapping quality indicators for the information provided. Furthermore, a technical e-book and a theoretical book—available in both printed and e-book formats—were developed. These publications focus on vaccination coverage and examine the situation in the Americas, Brazil, and the state of São Paulo, including chapters on methodologies and concepts.
