Effects of influenza vaccination on the morbidity and severity of COVID-19 in children

The pandemic of a new coronavirus infection COVID-19 initiated research to find methods of non-specific influence on the immune system that can change the course of infectious diseases. Adult study results have been demonstrated the positive effect of seasonal influenza vaccination on morbidity, hospitalization rates, and reducing the severe forms of SARS-CoV-2 infection. That suggests a similar action in children.   The aim of the study: to establish the possible impact of influenza vaccination on the morbidity and severity of COVID-19 in children in Volgograd.   Materials and methods. The 303 children 3-17 years old without a history of chronic diseases were included in comparative prospective cohort study on the impact of influenza vaccination (235/303) on morbidity and severity of a new coronavirus infection COVID-19 vs non-vaccinated group (68/303).   Results. All children with new coronavirus infection COVID-19 (diagnosis confirmed by laboratory testing - U07.1) had mild symptoms of the disease. In all age groups, the morbidity and the severity of the new coronavirus infection COVID-19 among children vaccinated against influenza did not have significant differences with non-vaccinated group.   Conclusion. The results of our study did not support the hypothesis of a protective role of seasonal influenza vaccination on the morbidity and severity of COVID-19 in healthy children. Further research is needed to establish the effect of influenza vaccination on the severity of COVID-19 in children with chronic diseases.