Post-COVID syndrome in children: the results of a retrospective multicenter cross-sectional study
Authors: Tsarkova Sofya A. , Zaytseva Olga V. , Lokshina Evelina E. , Zaytseva Svetlana V. , Isaeva Elena P. , Murtazaeva Olga A. , Ermakova Margarita K. , Pavlinova Elena B. , Vavilova Vera P. , Petrushina Antonina D. , Faizullina Reseda M. , Shangareeva Ziliya A. , Bochkareva Nataliya M. , Yashkina Olga N. , Peterson Kristina Iu. , Selivanov Artem A. , Shikina Elizaveta A. , Kaib Irina D. , Kulichenko Marija P. , Khalidullina Oksana Iu. , Ushakova Svetlana A. 
Published: June 2024

Background. Currently, there are no multicenter studies to determine the prevalence and incidence of symptoms of post-COVID syndrome (PCS) in children in different age groups, to develop consistent observation algorithms, and to identify therapy options.
Aim. To establish the risk factors for PCS in children and its CSs in the Russian Federation.
Materials and methods. A retrospective multicenter cross-sectional study was conducted. The initial stage of the study included 565 children at 7.6±0.17 months after the new coronavirus infection (NCVI) who were on outpatient or inpatient observation in different regions of Russia from November 2022 to May 2023. Patients were selected from 9 regions of the Russian Federation, such as Izhevsk, Kemerovo, Moscow, Omsk and Omsk region, Yekaterinburg and Sverdlovsk region, Ufa, Tyumen, Samara, Naberezhnye Chelny. All patients were offered a questionnaire. The questionnaire was developed and adapted based on the British and American consensus on the PCS, which included an assessment of the history, severity of the disease, clinical form of acute NCVI, therapy in the acute period of NCVI, and the presence of comorbidities. In addition, the course of acute NCVI and symptoms 3 months after the disease were evaluated by the following groups of CS: asthenia, respiratory disorders (RD), gastrointestinal disorders (GI), neurocognitive disorders (NCD), skin/adnexal lesions, olfactory/taste disorders, autonomic dysfunction (AD), anxiety. Of the 565 questionnaires received, 435 (76.9%) met the inclusion criteria and were available for subsequent analysis. The mean age was 9.0±0.25 years.
Results. During the acute period of the NCVI, asthenic syndrome (AS), RD and NCD, anxiety symptoms, olfactory/taste disorders, manifestations of AD, GI and skin/adnexal lesions were most often detected. Our study showed that after 3 months or more after NKVI, AS, NCD, and RD recurred in almost half of the observed children (53.1, 49.0 and 47.8%, respectively), anxiety was detected in 42,5% of cases, in more than 1/5 of children, AD, olfactory/taste and gastrointestinal disorders, in 14.3% skin/appendage lesions. Even 90 days after recovery from NCVI, more than half of patients reported impaired functionality, and most children had multiple complaints, which significantly impaired their quality of life. The risk of developing certain manifestations of PCS was increased in patients with comorbidities.
Conclusion. The study found that PCS developed in patients with severe, moderate, and mild acute COVID-19. The presence of comorbidities (allergic, neurological diseases, ENT disorders) statistically significantly increased the risk of PCS. The study's results further confirm the importance of continuous monitoring of NKVI sequelae in children and adolescents and the need for follow-up in children recovered from NKVI for 3-12 months.