Features of respiratory syncytial virus infection in children in the post-COVID-19 era

Abstract

Respiratory syncytial virus (RSV) infection in children is a major public health problem, especially in the 0-1 year age group where clinical forms of the disease can evolve severely with life-threatening complications. In the period 2020 – 2022, as a result of epidemiological measures specific to the COVI-19 pandemic (protective mask, online teaching activity, social distancing) we have witnessed a considerable decrease in the number of cases of RSV infection in children. With the lifting of prophylactic measures and the onset of the cold season, we have seen an increase in the number of admissions with a diagnosis of respiratory virus in pediatric wards. In this article, we aim to analyze the clinical, evolutionary and epidemiological features of respiratory syncytial virus infection in children in the 2022 - 2023 season. We conducted a retrospective clinical study of RSV infection cases admitted to the Pediatric Infectious Diseases Clinical Departments of the National Institute of Infectious Diseases “Prof. Dr. Matei Bals” in the period October 2022 - March 2023. During this period, we registered 195 cases of RSV infection in children, which represents 6.47% of the total number of hospitalized virologic illnesses in children (195/3012). All pediatric RSV infection cases admitted to our wards have progressed favorably; we have not recorded any deaths. From an epidemiological point of view, the peak incidence of RSV infection in children occurred in December (98 cases). The most frequent clinical form of the disease was the medium form, but severe forms represented 31.8%. Among the complications, the most common were respiratory (acute respiratory failure, pneumonia/bronchopneumonia), hematological (intrainfectious and deficiency anemia, leukopenia, thrombocytopenia), digestive (diarrheal disease, hepatic cytolysis syndrome) and acute dehydration syndrome associated with hydro electrolytic and acid-base disturbances. Severe complications were more frequent than in previous seasons, being associated with a risk of an unfavorable outcome: acute respiratory failure and neurological complications (convulsions, encephalitis). We also observed that acute RSV infection in the 2022 - 2023 season is characterized by the association of co-infections (viral, bacterial and fungal) more frequent than in previous years (22.5%). The most frequent co-infections were bacterial (superinfections - pneumonia/bronchopneumonia) probably due to the immunosuppression of the hosts as a result of repeated recent episodes of viral infections. Of note, RSV infection associated with other coinfections evolved more severely, with prolonged hospitalization and more complications. In conclusion we can say that RSV infection in the 2022 - 2023 season evolved more severely in children compared to previous seasons because in the last 3 years during the COVID-19 pandemic there were very few cases of respiratory viroids, thus the population was not naturally immunized, especially the age group 0 - 4 years. In addition, the abandonment of specific protective measures for respiratory diseases has “exploded” the number of respiratory illnesses in the pediatric population, especially in children.