Cobertura vacinal infantil no brasil: fatores determinantes do declínio da imunização e seus impactos em saúde pública.

Abstract

Childhood vaccination represents one of the most effective public health strategies for disease prevention, playing a crucial role in reducing child morbidity and mortality and in eradicating vaccine-preventable diseases. In Brazil, the National Immunization Program (PNI), established in 1973, stands out as one of the most successful health policies of the Unified Health System (SUS), ensuring free, equitable, and universal access to immunobiologicals. However, in recent decades, a concerning decline in vaccination coverage—particularly among children aged 0 to 5 years—has been observed, threatening herd immunity and facilitating the resurgence of previously controlled diseases such as measles and poliomyelitis. This study aims to analyze the determining factors behind this decline, identifying logistical, social, and communicational challenges that hinder adherence to the national childhood immunization schedule. A comprehensive literature review was conducted, covering the period from 2014 to 2023, with searches in databases such as SciELO, PubMed, Bireme, and Google Scholar, in addition to the analysis of secondary data from the National Immunization Program Information System (SIPNI), the Primary Health Care Information System (SISAB), the Notifiable Diseases Information System (SINAN), and the National Council of Municipal Health Secretariats (CONASEMS). The results indicate that vaccine hesitancy, amplified by misinformation and the anti-vaccine movement, has become one of the main contributors to reduced vaccination coverage. Furthermore, regional inequalities, logistical failures in vaccine distribution, occasional shortages, and the overload of the health system during the COVID-19 pandemic have exacerbated the problem. The North and Northeast regions show the greatest disparities in access, reflecting the impact of socioeconomic and structural inequalities on achieving national vaccination goals. The analysis also shows that the MMR (measles-mumps-rubella) vaccine exhibits the highest dropout rates, while pneumococcal and meningococcal C vaccines demonstrate more favorable progress. These findings highlight that, although the PNI remains a cornerstone of Brazilian public health, reinforcing public communication policies, strengthening epidemiological monitoring, and implementing outreach and school-based vaccination strategies are essential. In conclusion, restoring high vaccination coverage requires integrated, intersectoral, and sustained actions involving policymakers, health professionals, educators, and communities. Reversing the decline in childhood immunization is vital not only to safeguard individual health but also to preserve a collective achievement built over decades of public health efforts in Brazil.