Scarlet fever
Version: November 2025
Introduction
Scarlet fever is an infectious disease caused by the bacteria Streptococcus pyogenes, also known as Group A Streptococcus. It primarily affects children between the ages of 5 and 15. The disease is characterized by a distinctive red rash that feels like sandpaper, fever, and a sore throat. It occurs when the bacteria produce a toxin leading to the rash. Scarlet fever is transmitted through respiratory droplets from coughing or sneezing. Though historically considered a serious illness, it can now be effectively treated with antibiotics, reducing the risk of complications significantly.
Highlights
- Disease Activity Fluctuation: Scarlet fever cases in mainland China show considerable monthly fluctuations, with peaks often observed around May and December each year.
- Case Reduction Post-Peak: Following high case numbers in 2020, a marked reduction in cases is evident by November 2025, stabilizing at lower levels compared with previous years.
- Zero Mortality Recent Trend: Since an isolated death in 2020, no further deaths have been reported, emphasizing improved disease management or treatment outcomes.
- Suppressed Winter Spike: While winter months often saw increased cases, the trend in November 2025 suggests a subdued seasonal peak compared to prior years.
Analysis
Cases Analysis
The Scarlet fever data in mainland China shows distinct seasonal fluctuation patterns, with cases increasing towards the end of the year and peaking in winter months. From 2015 to 2019, we observe a consistent rise in cases from October through December, followed by a decline in early months like January and February. Mid-year months such as May and June occasionally see a secondary spike before cases dip in August and September. This pattern aligns with the seasonal occurrence of respiratory illnesses, often influenced by colder weather conditions conducive to disease spread.
Remarkably, the death toll remains almost negligible with two exceptions in 2020, indicating effective healthcare management of the disease. Interestingly, 2020 marks a significant drop in cases, likely attributable to public health measures and behavioral shifts due to the COVID-19 pandemic. Increased public attention to hygiene and social distancing during this period likely curtailed the transmission of various infectious diseases, including Scarlet fever. Subsequent years, particularly 2023 and 2024, show an uptick in cases, suggesting a gradual return to pre-pandemic patterns, although not reaching previous peaks, indicating a societal adaptation phase. This data underscores the interplay between public health measures and disease incidence, illustrating how interventions can alter typical epidemiological cycles.
Deaths Analysis
The data on Scarlet fever in mainland China from November 2015 to November 2025 shows exceedingly low mortality despite fluctuations in reported cases. The figures reveal a recurring pattern, with case peaks often occurring from April to June each year, yet only two deaths were reported—one in January 2020 and another in September 2020. This indicates an exceptionally low fatality rate for Scarlet fever across the decade, suggesting effective public health measures, early diagnosis, timely treatment, or a typically mild disease course. Nonetheless, maintaining vigilance is crucial due to potential complication risks and the enduring transmission burden.
Significant variances are noted in case counts, and a marked reduction in cases is observed starting in early 2020, likely due to COVID-19-related restrictions impacting person-to-person transmission. Subsequent years show a gradual case rebound, but mortality remains close to zero, supporting effective disease management. The overall handling of Scarlet fever in China appears successful, minimizing fatalities while the disease burden, in terms of cases, warrants continuous surveillance and interventions to limit transmission, especially during peak outbreak months. Continued public health efforts should focus on reducing spread and maintaining the observed low mortality trend, underscoring the importance of ongoing strategy enhancements and societal health initiatives.