Article in Japanese

Clinical characteristics of pediatric patients diagnosed with COVID-19 during the severe acute respiratory syndrome coronavirus 2 omicron-predominant period in Toyama Prefecture

Takuya WADA^1）, Hiromichi TANEICHI^2）, Tomomi TANAKA^2）, Kiyoshi HATASAKI^3）, Noboru IGARASHI^3）, Kazuhiro WATANABE^4）, Harue TSUJI^5）, Michio KONISHI^6）, Shinichi YAGI^7）

Limited data are available on the clinical characteristics of pediatric patients with coronavirus disease (COVID-19) infection during the severe acute respiratory syndrome coronavirus 2 omicron-predominant period in Japan. We compared the clinical characteristics of omicron subvariants BA.1/BA.2 and BA.5 in pediatric inpatients and outpatients diagnosed with COVID-19 in Toyama Prefecture between January and September 2022. The study included 6996 patients enrolled across 13 hospitals and 13 clinics；4974 patients were aged ＜10 years and accounted for 23.1％ of the total number of cases across Toyama Prefecture during the same period. We investigated 3520 patients during the BA.1/BA.2 and 3476 patients during the BA.5-dominant periods. Fever, cough, and sore throat were the most common symptoms, in that order, during both waves. The prevalence of seizures among 1‒4 year-olds and vomiting, abdominal pain, seizures, and delirium among 5‒11 year-olds was significantly increased during the BA.5-dominant period (from July 2022). The number of patients who required intravenous fluid transfusion therapy was significantly high during the BA.5-dominant period. A small number of patients required oxygen and noninvasive respiratory support during each wave; however, most patients did not develop severe illness. Pediatric patients did not present with severe disease during the omicron-predominant period. Further studies are warranted to investigate the effects of new mutant strains on the clinical symptoms and severity of COVID-19 infection in pediatric patients.

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1）Department of Pediatrics, Toyama City Hospital
2）Department of Pediatrics, Faculty of Medicine, University of Toyama
3）Toyama Prefectural Rehabilitation Hospital & Support Center for Children with Disabilities
4）Department of Pediatrics, Kurobe City Hospital
5）Department of Pediatrics, Takaoka City Hospital
6）Department of Pediatrics, Tonami General Hospital
7）Yagi Pediatric Clinic

Key words	severe acute respiratory syndrome coronavirus 2, coronavirus disease 2019，omicron variant，children
Received	April 13, 2023
Accepted	June 5, 2023

35 (3)：235─243,2023