Abstract:

Objective To investigate the clinical characteristics of children infected with coronavirus disease 2019（COVID⁃19）and to analyze the differences between children vaccinated against coronavirus vaccine and those not vaccinated. Methods Sixty⁃six COVID⁃19 cases（< 14⁃year⁃old）who were admitted to Hangzhou Sixth People′s Hospitalfrom January 21，2020 to April 28，2022 were selected and assigned to vaccinated group （n = 40）and unvaccinated group（n = 26）according to whether they had received vaccine or not. The clinical characteristics，laboratory data and average hospitalstays were compared between the two groups. Results There was no statistical significance in the incidence of clinical symptoms between the two groups（P > 0.05）；the count of white blood cells，lymphocytes，neutrophils and eosinophils were decreased and the count of platelet was increased in both groups，and there was no statistical significance in the decrease rates of the above indicators and the increase rates of platelet counts（P > 0.05）；AST，LDH and CK⁃MB were increasedin all the children between two groups，and the increase rate of LDH in the unvaccinated group was higher than that of the vaccinated group，with statistical significance（P < 0.05），and there was no statistical significance in the increased rates of AST and CK⁃ MB between two groups（P > 0.05）；Statistical significance was found in average hospital stay（10.1 ± 5.5 vs. 16.4 ± 13.0 days，P < 0.01 and IgG antibody titer（147.7 ± 140.9 vs. 79.5 ± 114.1 AU/mL，P < 0.05）between the vacci⁃ nated and unvaccinated group. Conclusions This study showed that the clinical symptoms of children infected with COVID⁃19 were mostly mild，and severe and critical illnesses are less frequent. Most of the children had liver function damage and myocardium inflammation. The inflammatory damage of the children in the vaccinated groupwas milder. The covid⁃19 vaccine may be the key to reduce the inflammatory damage，shorten the hospitalization and fasten physical recovery in children.

Key words:

SARS?CoV?2, children, vaccine