Clinical and Epidemiological Characteristics of Scarlet Fever in Russia

Relevance. In recent decades, large outbreaks of scarlet fever have been reported in European and Asian countries. Severe forms of the infection have become more frequent and the number of complications has also increased. Aim. To assess the incidence of scarlet fever in the Russian Federation using the official statistical sources, to identify the clinical features of scarlet fever among adults. Materials and methods. Analysis of the level and dynamics of the long-term incidence of scarlet fever in the entire population and among different age groups in Russia from 1890 to 2021 was performed based on the data of annual statistical forms. A clinical and epidemiological descriptive retrospective census study was conducted using data from the case histories of patients diagnosed with “scarlet fever” in The Infectious Disease Clinical Hospital No. 2 Moscow Healthcare Department from 2010 to 2022. Results. Three major cycles (40-50 years) can be distinguished in the long term with regard to incidence. In 1986, the rise in incidence was noted after 30 years since the previous one and it was less intensive. In the first cycle, rates increased gradually over almost 10 years beginning from 1891. In subsequent years, the incidence remained high (220-280 per 100,000), decreasing markedly to 50-60 per 100,000 population only by 1917-1918. The second cycle, from 1918 to 1942, was characterized by increasing rates (up to 462 per 100,000 population). In the third cycle (1946 - 1981), incidence rate reached a peak by 1955 (531.8 per 100,000 population), and started to gradually decrease afterwards. There were cycles lasting 3–6 years in in this period The fourth cycle (1982-1991) was not so large. In recent years (2007–2021), the incidence decreased 7.3 times (from 45.4 to 6.2 per 100 thousand). The average incidence rate during this period was 29.8 per 100 thousand. In 2022, the incidence of streptococcal infection increased 2.8 times (including scarlet fever – 3 times). The incidence increases were observed in the group 0-14 years and 14 and older (from 298,2 to 34,1 and from1,6 to 0,1respectively). As in the previous years (fourth cycle), children aged 3-6 years were the main contributors to the incidence of scarlet fever (the average incidence rate – 452,1 per 100,000). The average age of patients admitted to the hospital was 24 years (18–45 years). There was an increase in the average age of patients since 2017. During the study period, the number of hospitalized adults with scarlet fever decreased by half. In most cases (98.56%) the patients had a moderate condition at admission and only 3 had a severe condition (1.44%). The most common comorbid diagnoses were ENT-organs infections (9%), urinary tract infections (3.35%) and Wolf-Parkinson-White syndrome (2.87%). Scarlet fever had a complicated course of infection in 19 patients (9.09%). In the treatment were used cephalosporin (52.63%) and penicillin (41.63%). Conclusions. This study demonstrated a stable downward trend in the incidence of scarlet fever in the population of the Russian Federation in recent years until 2021. In 2022, the incidence increased 3 times (18.7 per 100 thousand). The number of hospitalizations among adults with scarlet fever and the number of patients with complications have decreased. The average age of patients by 5 years have increased. The treatment was carried out in accordance with clinical recommendations and the antibiotic resistance of the pathogen.