Correlation with existing literature

Our findings of a marked rise in hospitalizations for congenital syphilis, with strong regional variation, are consistent with the broader literature documenting a sustained and spatially expanding epidemic of congenital syphilis across Brazil. Multiple spatiotemporal analyses have shown steep increases in incidence, particularly in the South, Southeast, and Central-West regions, and the spread from coastal urban centers into inland municipalities characterized by social vulnerability and incomplete prenatal care. ^{Reference Dalazen, de Souza and Ribeiro2,Reference Silva, Leony and de Souza3,Reference Lannoy, Santos and Coelho7,Reference Medeiros, Yamamura and da Silva15–Reference Dantas, Marinho and Pinheiro19} These studies corroborate our observation that congenital syphilis is the main driver of hospitalization trends and disproportionately affects regions with weaker maternal health infrastructure. By contrast, the lack of robust surveillance data for other congenital infections in the literature parallels our finding that their hospital burden, although relevant, is less well characterized and receives limited public health attention.

The high volume of hospitalizations, prolonged stays, and increased costs documented in our study resonate with evidence from LMICs showing that congenital infections impose disproportionate clinical and economic burdens compared with high-income countries. Paixão et al, ^{Reference Paixão, Carroll and Rodrigues8} demonstrated that children with congenital syphilis in Brazil faced a six-fold higher risk of hospitalization, particularly in the neonatal period, aligning with our finding of syphilis as the predominant cause of infant admissions. Similarly, the elevated resource demands we observed for cytomegalovirus and herpes mirror global reports of higher birth prevalence of congenital cytomegalovirus in LMICs and longer, costlier hospitalizations for neonatal herpes. ^{Reference Velaphi, Madewell and Tippett-Barr20–Reference Lee, Gottlieb and Chaiyakunapruk23} Although rubella hospitalizations declined in our analysis, evidence from China indicates that congenital rubella syndrome still carries the highest individual economic burden among TORCH infections. ^{Reference Zhang, Wang and Liu22} These parallels reinforce that congenital infections, especially syphilis and cytomegalovirus, remain major drivers of pediatric hospital resource utilization in resource-limited settings.

In 2008, SUS implemented a nationwide rubella vaccination campaign that immunized 67.9 million individuals, achieving 96.7% coverage of the target population of adults aged 20–39 years, with additional inclusion of adolescents aged 12–19 years in selected states. Following five consecutive years without documented endemic transmission, Brazil was officially certified as having eliminated rubella in 2015. ²⁴

The persistent rise in congenital syphilis hospitalizations underscores limitations of Brazil’s prevention strategies despite national initiatives (Figure 3). Interrupted time series analyses show some reductions in high-burden municipalities after targeted interventions, but overall incidence remains high compared with high-income countries. ^{Reference Pinto, Valentim and Fernandes da Silva25} Regional differences in hospitalization rates align with evidence of unequal primary care performance, especially in partner management and health education. ^{Reference Couto, Castanheira and Sanine5} Although national treatment coverage exceeds 80%, congenital syphilis has continued to rise, diverging from the declining trajectories of HIV and hepatitis B²⁶. The pandemic’s disruption of prenatal services, reflected in delayed diagnoses, may also have contributed to the hospital burden observed. ^{Reference Echegaray, Hernandez and Sundar27} For toxoplasmosis, steady hospitalization growth is consistent with literature showing Brazil’s higher burden than high-income countries, driven by environmental risk factors, late maternal diagnoses, and absent systematic prenatal screening. ^{Reference Strang, Ferrari and do Rosário28,Reference Vivacqua, Paz and Frota29}

Figure 3.

Major milestones in the Brazilian Unified Health System (SUS) response to congenital infections, 2000–2024.

In addition to true increases in disease burden, improvements in diagnostic capacity and test utilization may have contributed to the rising number of hospitalizations observed over time. Greater awareness and improved adherence to diagnostic protocols may have reduced underdiagnosis. As a result, part of the observed increase in hospital admissions may reflect enhanced case detection rather than a proportional rise in incidence.

An important aspect of our findings concerns Brazil’s persistent regional inequalities shaping the burden of congenital infections. The North and Northeast, marked by lower socioeconomic indicators, limited health infrastructure, and poorer prenatal care, consistently showed higher hospitalization rates due to structural barriers such as fewer specialized maternity services, lower syphilis and toxoplasmosis screening coverage, and limited laboratory capacity. In contrast, the more developed South and Southeast, with greater availability of tertiary hospitals, exhibited lower hospitalization rates but higher costs and ICU use, reflecting more advanced case management and broader access to intensive care. This geographic barrier to accessing healthcare in the North and Northeast has already been identified in previous studies. ^{Reference Albuquerque, Felipe, Lopes, Tassinari, Zicker and Fonseca30,Reference Isaacson, Joiner and Kozhumam31}

Limitations and strengths

Several limitations must be considered. First, the retrospective, population-based time series design has cohort-like features but is not a true cohort, as it analyzes population-level hospital records rather than individual follow-up; nonetheless, the 17-year span and repeated measures permit meaningful assessment of temporal trends. Second, reliance on DATASUS SIH, a robust yet limited secondary database dependent on ICD-10 coding accuracy, introduces risks of underreporting, misclassification, and regional variability, especially for less frequent congenital infections that constitute a small proportion of infant hospitalizations and may not appear among leading causes of admission. Moreover, changes over time in surveillance practices, diagnostic capacity, and reporting quality may have contributed to apparent increases in hospitalization rates, reflecting improved case detection rather than true changes in disease incidence. Individual clinical outcomes, such as neurological sequelae, hearing loss, congenital malformations, cannot be assessed because the database provides only hospitalization-related proxies. Third, regional differences in healthcare infrastructure and resource availability may influence observed patterns, including higher ICU utilization in more economically developed regions, which may reflect greater access, heightened clinical awareness, or lower thresholds for admission rather than differences in disease severity alone; these factors may also partially explain regional disparities in mortality. Fourth, it was beyond the scope of this study to analyze the incidence of the infections among the general population (all ages), which limits conclusions on transmissibility. Finally, causality between public health interventions and observed trends cannot be established.

Despite these limitations, the study has notable strengths. It is the first nationwide, long-term analysis of the hospital burden of multiple congenital infections in Brazil, integrating data on hospitalization rates, costs, length of stay, ICU use, mortality, and regional disparities. Standardized, publicly accessible data support transparency and reproducibility, and the extended observation period captures temporal patterns missed by shorter studies. By analyzing infections collectively, the study offers a comprehensive perspective critical for policy planning, resource allocation, and strengthening maternal–child health networks.

From a public health perspective, these findings offer actionable insights for Brazil’s Unified Health System. Nationwide analyses based on DATASUS data are routinely used by health authorities to inform planning and resource allocation. By quantifying hospitalizations that are largely preventable through effective prenatal screening and timely treatment, our results highlight opportunities for cost avoidance and efficiency gains. The pronounced regional disparities in mortality further support the need for targeted investments in prenatal care and diagnostic capacity, particularly in the North and Northeast.