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March 17, 2026Open Access

Re-Emergence of Pertussis and Performance of Primary Care: Relationship With Low Pentavalent Vaccine Coverage in a Municipality in São Paulo State

Key Points

The study aims to assess the relationship between pertussis incidence and pentavalent vaccine coverage in infants under 1 year in Jacareí-SP.
Descriptive, retrospective, and quantitative design.
Analysis of secondary data from Notifiable Diseases Information System (SINAN).
Included suspected pertussis cases reported from 2012 to March 2025.
Vaccination status of infants under 1 year was compared with PNI targets.
A total of 170 suspected pertussis cases were reported, with 31 confirmed.
Among confirmed cases, 64.5% were in infants under 1 year.
Confirmed pertussis prevalence was 0.87 per 1,000 live births.
The odds of non-vaccinated infants contracting pertussis were 19 times higher than those with adequate vaccinations.
Vaccine coverage did not reach the 95% target in 2023 and 2024.

Abstract

Pertussis is a bacterial respiratory infection caused by Bordetella pertussis, with greater severity in children under 1 year of age. The National Immunization Program (PNI) schedule recommends three doses of pentavalent vaccine in the first six months of life. Declining vaccination coverage may favor disease resurgence and compromise quality indicators of Primary Health Care (PHC), negatively influencing the transfer of federal resources. This study aims to analyze the correlation between pertussis incidence and pentavalent vaccine coverage in Jacareí-SP between 2012 and 2025, focusing on the population under 1 year of age. Descriptive, retrospective and quantitative study based on secondary data from the Notifiable Diseases Information System (SINAN) and municipal vaccination coverage data. Suspected cases notified between 2012 and March 2025 were included, with analysis of vaccination status in infants under 1 year and comparison with PNI targets. A total of 170 suspected cases were notified, with 31 confirmed (18.2%). Of these, 20 (64.5%) occurred in children under 1 year, and 95% had incomplete or not initiated vaccination schedules. The prevalence of confirmed pertussis in infants under 1 year in the period was 0.87 per 1,000 live births. The approximate odds ratio of a non-vaccinated or incompletely vaccinated infant being diagnosed with pertussis was 19 times higher compared with those with adequate vaccination (OR = 19.0; 95% CI: 3.7–97.1). The highest peaks occurred in 2013 and 2014. The reduction in notifications between 2020 and 2023 coincides with the COVID-19 pandemic. Pentavalent vaccine coverage did not reach 95% in 2023 and 2024, according to official data, indicating risk of disease re-emergence and loss of performance based PHC funding. Low pentavalent vaccine coverage is directly associated with increased pertussis cases in infants, reflecting failures in immunization and non-achievement of PNI targets. Expanding coverage is essential to prevent outbreaks, protect vulnerable populations and ensure financial sustainability of PHC. Strategies such as active case-finding, team training, improved records and educational actions are crucial to reverse this scenario.

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