Análise dinâmica da cobertura vacinal da poliomielite no Estado de São Paulo de 2016 a 2022

Abstract

Introduction: Childhood vaccination is a preventive health measure, with a great impact on reducing child morbidity and mortality, avoiding 2 to 3 million deaths per year, according to the World Health Organization. In addition to being effective, vaccination has a lower cost to the health system by preventing a disease than treating it, which in the case of paralyzing poliomyelitis occurs an irreversible clinical state, which can prevent you from walking or breathing on your own. A cruel condition, as it affects children under five years of age in most cases, generating sequelae for the rest of their lives. In recent years there have been cases even in countries that have the poliovirus under control. In addition, since 2015, Brazil and neighboring countries have shown progressive drops in vaccination coverage, increasing the risk of poliovirus reintroduction. Objective: to analyze the spatial dynamics of polio vaccination coverage in the state of São Paulo from 2016 to 2022. Methods: mixed ecological study using secondary data from the public domain. The doses of the polio vaccine administered were obtained from the National Immunization Program information system, and information on the number of live births was obtained from the Live Birth Information System of the Unified Health System database. Polio vaccination coverage rates were calculated by municipality and year. Descriptive analysis of vaccination coverage, Kruskal-Wallis and Dunn's multiple comparisons tests, Chi-square test and spatial analysis with the construction of thematic maps were performed. The significance level was 5%. Results: It was identified that there is a difference between the years (Kruskal-Wallis test, p < 0.001), by Dunn's multiple comparisons test, showing that 2016 differs from the other years, and that 2020, 2021 and 2022 differ from each other and from previous years (p < 0.01). In the spatial analysis, a drop in polio vaccination coverage was observed from 2016 to 2021, the year that had the lowest polio vaccination coverage, with approximately 70% of the municipalities (442) with a low rate in the four macro-regions (p<0.001), below the target recommended by the Ministry of Health (95%). The COVID-19 pandemic proved to be a factor contributing to the drop. With the presence of low-low clusters predominantly in the fourth macro-region (south-east) and high-high clusters in the first macro-region (north-west), corresponding to the same weight of significance in the maps, over the course of the seven years analyzed. In the last year analyzed, 2022, with the arrival of campaigns and actions aimed at polio vaccination, there was a change in vaccination coverage, with an increase in approximately 95% of the municipalities (610) with a high rate in the four macro-regions (p<0.001). Conclusion: Knowing the immunization scenario is important to apply strategic actions and more effective public policies in order to improve child health, avoiding the risk of reintroduction of poliomyelitis in the state of São Paulo.