In this retrospective, single-center study, we conducted an analysis of 13,699 samples from different individuals obtained from the Federal Research Center of Fundamental and Translational Medicine, from 1 April to 30 May 2020 in Novosibirsk region (population 2.8 million people). We identified 6.49% positive for SARS-CoV-2 cases out of the total number of diagnostic tests, and 42% of them were from asymptomatic people. We also detected two asymptomatic people, who had no confirmed contact with patients with COVID-19. The highest percentage of positive samples was observed in the 80+ group (16.3%), while among the children and adults it did not exceed 8%. Among all the people tested, 2423 came from a total of 80 different destinations and only 27 of them were positive for SARS-CoV-2. Out of all the positive samples, 15 were taken for SARS-CoV-2 sequencing. According to the analysis of the genome sequences, the SARS-CoV-2 variants isolated in the Novosibirsk region at the beginning of the pandemic belonged to three phylogenetic lineages according to the Pangolin classification: B.1, B.1.1, and B.1.1.129. All Novosibirsk isolates contained the D614G substitution in the Spike protein, two isolates werecharacterized by an additional M153T mutation, and one isolate wascharacterized by the L5F mutation.

We investigated the incidence of 15 respiratory viruses among 2991 children with acute respiratory infections in Novosibirsk city, Russia, prior to the COVID-19 pandemic (2013–2020). Viral infections were detected in 72.5% cases. The incidence of human coronavirus was 2% (Alphacoronaviruses, 63%; Betacoronaviruses, 37%).

Introduction. Metapneumovirus frequently causes respiratory tract infections in children worldwide, with clinical manifestations ranging from mild upper respiratory tract disease to severe bronchiolitis and pneumonia. However, not all countries conduct regular metapneumovirus infection monitoring that complicates its infection trend analysis. The aim of the work was to analyze the etiological pattern of acute respiratory diseases by assessing proportion of metapneumovirus infection, as well as comparatively assess clinical characteristics of the main acute respiratory viral infections in children in Novosibirsk. Materials and methods. Between November 2019 and May 2024, from children aged 0–17 years, admitted with symptoms of acute respiratory diseases there were collected and analyzed 6468 samples for metapneumovirus and other respiratory viruses using real-time polymerase chain reaction. Results. Viral etiology of acute respiratory diseases in hospitalized children was confirmed in 63.0% (4077/6468) of cases. The etiological ARVI pattern differed significantly in various epidemic seasons. Thus, in 2019–2020, influenza virus (27.8%) and respiratory syncytial virus (21.1%) dominated in the etiology of acute respiratory viral infections, while metapneumovirus was detected only in as few as 1.6% of children. In contrast, in 2020–2021, we observed a sharp increase in the detection rate of metapneumovirus (28%) paralleled with the absence of influenza virus and RSV. At the same time, in the following season (2021–2022) we did not detect any cases of metapneumovirus infection. In the following two seasons, the detection rate of metapneumovirus was about 5%: in children aged 3–6 years it was significantly higher than in infants and children aged 7–17 years. Clinical signs of metapneumovirus infection included fever, cough, dyspnoea, hypoxia and were similar to the manifestations of respiratory syncytial virus infection. At the same time, fever above 39°C and malaise were significantly more frequent in patients with influenza. Conclusion. Understanding the epidemiology of specific respiratory infections, compared with global trends, can help to develop targeted prevention and control measures.