Features of clinical and laboratory changes in adolescents in the dynamics of novel coronavirus infection

The relevance of research on a novel coronavirus infection is associated with an increase in the incidence among children since 2021, which may be due to the accumulation of mutations in the virus genome and its evolution towards increased contagiousness, replicative ability, and evasion of immune protection. While there are many studies in adults, data analyzing the clinical course of the disease in pediatric patients infected with SARS-CoV-2 are limited, particularly regarding adolescents. Objective. To study the clinical and laboratory features of the course of a novel coronavirus infection in hospitalized adolescents in Novosibirsk during the first, second and third waves of the pandemic. Мaterials and methods. A retrospective analysis of case histories of 125 children treated at Novosibirsk Children's Clinical Hospital No 6 with a confirmed diagnosis of coronavirus infection during three pandemic waves was carried out (June–August 2020, October–December 2020, June–August 2021). Based on these time intervals, three groups of adolescents admitted to the hospital during the first, second, and third waves of coronavirus infection were formed. SARS-CoV-2 RNA in nasopharyngeal and oropharyngeal scrapings was determined using the PCR-RT method. Biochemical and general clinical studies were performed in accordance with the guidelines of the Ministry of Health of the Russian Federation. Statistical processing was carried out using the Satistika 7.0 software package (StatSoft, USA). Differences between the groups were assessed using the Z-test and the Mann–Whitney U test. Differences between the compared series were considered statistically significant with a probability level of 95%. Results. It was shown that during three pandemic waves (June 2020 – August 2021), more than half of the hospitalized children were adolescents. At the same time, regardless of the pandemic wave, intoxication, catarrhal and intestinal syndromes predominated in hospitalized adolescents. CNS injury symptoms were significantly less frequent in the first wave, as were skin rashes. Cough in the third wave was observed in 100% of hospitalized adolescents. The average values of the parameters of complete blood count, as well as CRP, D-dimer and ferritin had no statistically significant differences in different pandemic waves, but there was a significant variation in individual values within the groups in each wave. Key words: adolescents, coronavirus infection, COVID-19, clinical manifestations, laboratory parameters