Epidemiological Characteristics of Scarlet Fever among Children in Henan Province, 2014-2024

Technical Summary: Epidemiological Characteristics of Scarlet Fever among Children in Henan Province, 2014-2024

Problem Statement
Scarlet fever, an acute respiratory infectious disease caused by Group A beta-hemolytic streptococcus, has shown an upward trend in incidence across China in recent years, with clustered outbreaks posing threats to child health and public safety. While the disease is classified as a Class B infectious disease in China, there is a need for deeper understanding of its epidemic patterns and clinical features in specific regions to optimize prevention and control measures. This study addresses the gap in detailed epidemiological data for Henan Province, aiming to analyze the characteristics of scarlet fever cases to provide scientific evidence for regional disease management.

Methodology
This retrospective study was conducted at the Affiliated Children's Hospital of Zhengzhou University (Henan Children's Hospital), the designated hospital for scarlet fever diagnosis and treatment in the province.

• Data Source: The study reviewed hospitalization records from January 1, 2014, to December 31, 2024.
• Selection Criteria: Initially, 703 cases were identified. After excluding cases with missing address information, cases from outside Henan Province, and duplicate data, 585 valid cases were retained for analysis.
• Diagnostic Criteria: Diagnosis relied on clinical symptoms (high fever, pharyngitis, strawberry tongue, diffuse rash) supported by laboratory tests, including blood routine, biochemical tests, throat swab bacterial culture, PCR, rapid antigen detection, and serological testing (anti-streptococcal hemolysin O titer).
• Statistical Analysis: Descriptive epidemiological methods were employed. The study calculated detection rates (cases per 10,000 inpatient admissions) and used chi-square tests to compare differences across groups. Quantitative data were analyzed using mean, median, and interquartile ranges (IQR). Software used included Excel for data organization, SPSS 27.0 for analysis, and Origin 2025b for graphing.

Key Results

• Temporal Trends: A total of 585 cases were detected over the 11-year period, with an annual average detection rate of 4.85 per 10,000 inpatient cases. The incidence showed a fluctuating pattern: a peak in 2017 (9.76/10,000), a decline to a low in 2020, and a rebound in 2021. The study identified two distinct seasonal peaks: May–June and November–January of the following year.
• Demographics:
  • Gender: Male patients significantly outnumbered females (356 vs. 229), with a ratio of 1.55:1.
  • Age: Onset was concentrated between ages 4 and 7 years. The 3–7 age group accounted for 71.3% of all cases. The median age was 4 years (IQR: 3–6).
  • Geography: Cases were heavily clustered in urban areas (77.4%), with Zhengzhou City accounting for 80.0% of all cases. Within Zhengzhou, Jinshui District had the highest concentration (39.5%).
• Clinical Characteristics:
  • Symptoms: Fever was present in 98.9% of cases (max 41°C), and rashes occurred in nearly all patients, with 66.1% experiencing itching. Pharyngitis and swollen tonsils were common.
  • Classification: Cases were categorized as common type (321 cases), toxic type (52 cases), and septic type (184 cases).
  • Complications: Respiratory complications were most frequent, including bronchitis (14.4%), pneumonia (13.3%), and tonsillitis (13.8%). Other complications included gastrointestinal symptoms (24.4%), liver damage, central nervous system symptoms, and Kawasaki disease.
  • Treatment & Outcome: Cephalosporins were the primary antibiotic used (78.1%). The median hospitalization duration was 5 days (IQR: 4–6). There were no reported deaths.
• Laboratory Findings: Patients exhibited significant inflammatory responses, with elevated C-reactive protein (mean 34.36 mg/L) and white blood cell counts (mean 14.30×10⁹/L), alongside neutrophilia.

Key Contributions
The study provides the first comprehensive 11-year epidemiological profile of scarlet fever in Henan Province based on data from a designated tertiary children's hospital. It characterizes the "peak decline - fluctuating decrease - gradual recovery" trend observed during the study period, specifically noting the 2017 peak and the 2021 rebound. The research highlights the strong regional clustering in Zhengzhou and the specific vulnerability of children aged 3–7 years. Furthermore, it documents the clinical spectrum of the disease in this region, confirming that while most cases are manageable with antibiotics, severe septic and toxic types do occur, necessitating vigilant monitoring for complications like sepsis and myocardial injury.

Significance and Limitations
The authors assert that these findings offer scientific evidence for formulating prevention and control strategies, emphasizing the "early detection, early reporting, early diagnosis, early isolation, and early treatment" approach. The data supports the need for enhanced health monitoring in collective settings like kindergartens and schools, particularly in urban centers like Zhengzhou.

However, the paper explicitly acknowledges several limitations that moderate the generalizability of its claims:

1. Single-Center Bias: As the data originates from a single designated hospital, it likely overestimates severe cases and underestimates mild cases treated in grassroots or outpatient settings, limiting its representativeness of the entire province.
2. Geographic Bias: The sample is heavily skewed toward Zhengzhou and urban areas, making it difficult to draw definitive conclusions about rural-urban differences or regional variations across Henan.
3. Etiological Gaps: The study lacks strain typing and drug resistance monitoring, preventing a detailed explanation of the etiological reasons behind annual fluctuations (e.g., the 2017 peak) or precise guidance on antibiotic resistance.
4. Lack of Controls: Without a healthy control group, the study cannot perform causal inference regarding risk factors such as climate, hygiene, or specific exposure risks, remaining at the level of describing phenomena rather than establishing causes.

Despite these limitations, the study concludes that scarlet fever in Henan exhibits clear regional clustering and age-specific susceptibility, warranting continued surveillance and targeted interventions for high-risk groups.