摘要Background SARS-CoV-2 continues to mutate over time,and reports on children infected with Omicron BA.5 are limited.We aimed to analyze the specific symptoms of Omicron-infected children and to improve patient care.Methods We selected 315 consecutively hospitalized children with Omicron BA.5 and 16,744 non-Omicron-infected febrile children visiting the fever clinic at our hospital between December 8 and 30,2022.Specific convulsions and body tempera-tures were compared between the two cohorts.We analyzed potential associations between convulsions and vaccination,and additionally evaluated the brain damage among severe Omicron-infected children.Results Convulsion rates(97.5％vs.4.3％,P＜0.001)and frequencies(median:2.0 vs.1.6,P＜0.001)significantly differed between Omicron-infected and non-Omicron-infected febrile children.The body temperatures of Omicron-infected chil-dren were significantly higher during convulsions than when they were not convulsing and those of non-Omicron-infected febrile children during convulsions(median:39.5 vs.38.2 and 38.6 ℃,both P＜0.001).In the three Omicron-subgroups,the temperature during convulsions was proportional to the percentage of patients and significantly differed(P＜0.001),while not in the three non-Omicron-subgroups(P=0.244).The convulsion frequency was lower in the 55 vaccinated chil-dren compared to the 260 non-vaccinated children(average:1.8 vs.2.1,P＜0.001).The vaccination dose and convulsion frequency in Omicron-infected children were significantly correlated(P＜0.001).Fifteen of the 112 severe Omicron cases had brain damage.Conclusions Omicron-infected children experience higher body temperatures and frequencies during convulsions than those of non-Omicron-infected febrile children.We additionally found evidence of brain damage caused by infection with omicron BA.5.Vaccination and prompt fever reduction may relieve symptoms.