tetano
Editor, Senior Moderator
J Infect Chemother
. 2026 Mar 9:102948.
doi: 10.1016/j.jiac.2026.102948. Online ahead of print.
Pediatric Coronavirus Disease 2019 Clinical Characteristics in a Primary Emergency Medical Center: Comparative Analysis of BA.1/BA.2, BA.5/BQ.1, and XBB Periods
Hiroshi Yamaguchi[SUP] 1 [/SUP], Tomohiro Sameshima[SUP] 2 [/SUP], Kazumichi Fujioka[SUP] 2 [/SUP], Tomoko Horinouchi[SUP] 2 [/SUP], Yoshitaka Asagai[SUP] 2 [/SUP], Hiroki Ohashi[SUP] 2 [/SUP], Tomoko Fujikawa[SUP] 2 [/SUP], Akihiro Nishimura[SUP] 2 [/SUP], Akihiro Tamura[SUP] 2 [/SUP], Shingo Ishimori[SUP] 2 [/SUP], Kandai Nozu[SUP] 2 [/SUP], Masaaki Kugo[SUP] 3 [/SUP], Akihito Ishida[SUP] 3 [/SUP]
Affiliations
Background: Differences in the clinical manifestation of pediatric coronavirus disease 2019 (COVID-19) across Omicron variants in emergency departments (EDs) remain unclear.
Patients and methods: This retrospective observational study characterized the clinical features of pediatric patients with COVID-19 for each variant period at a primary ED in Kobe City, Japan. The variant-dominant periods comprised BA.1/BA.2 (sixth wave, January-June 2022), BA.5/BQ.1 (seventh-eighth waves, July 2022-March 2023), and XBB (ninth wave, April-December 2023). COVID-19 was diagnosed by rapid antigen testing.
Results: Among the 46,719 pediatric ED visits, 4,085 were COVID-19 cases; 599 (9.0%), 2,943 (15.4%) and 543 (2.6%) cases were diagnosed in the sixth, seventh-eighth, and ninth waves, respectively. During the XBB period, cough was significantly more frequent than in other periods and nasal discharge was more common compared with the BA.5/BQ.1 period. Vomiting occurred more frequently in the BA.5/BQ.1 period than in the BA.1/BA.2 period. Among children aged <1 year, vomiting was significantly more common during the XBB period. No significant differences were observed between patients aged 1-4 years. Dyspnea was more common in the BA.1/BA.2 than in the BA.5/BQ.1 period. In adolescents, fever occurred more frequently during the BA.5/BQ.1 period.
Conclusion: This study compared pediatric COVID-19 cases across the BA.1/BA.2, BA.5/BQ.1, and XBB waves. Although evidence for the XBB wave remains limited, upper respiratory symptoms such as nasal discharge and cough were observed more frequently during this period. Distinct differences in clinical presentations according to variant type and age group were identified.
Keywords: Coronavirus disease 2019 (COVID-19); Emergency department; Omicron; Pediatric; Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
. 2026 Mar 9:102948.
doi: 10.1016/j.jiac.2026.102948. Online ahead of print.
Pediatric Coronavirus Disease 2019 Clinical Characteristics in a Primary Emergency Medical Center: Comparative Analysis of BA.1/BA.2, BA.5/BQ.1, and XBB Periods
Hiroshi Yamaguchi[SUP] 1 [/SUP], Tomohiro Sameshima[SUP] 2 [/SUP], Kazumichi Fujioka[SUP] 2 [/SUP], Tomoko Horinouchi[SUP] 2 [/SUP], Yoshitaka Asagai[SUP] 2 [/SUP], Hiroki Ohashi[SUP] 2 [/SUP], Tomoko Fujikawa[SUP] 2 [/SUP], Akihiro Nishimura[SUP] 2 [/SUP], Akihiro Tamura[SUP] 2 [/SUP], Shingo Ishimori[SUP] 2 [/SUP], Kandai Nozu[SUP] 2 [/SUP], Masaaki Kugo[SUP] 3 [/SUP], Akihito Ishida[SUP] 3 [/SUP]
Affiliations
- PMID: 41812825
- DOI: 10.1016/j.jiac.2026.102948
Background: Differences in the clinical manifestation of pediatric coronavirus disease 2019 (COVID-19) across Omicron variants in emergency departments (EDs) remain unclear.
Patients and methods: This retrospective observational study characterized the clinical features of pediatric patients with COVID-19 for each variant period at a primary ED in Kobe City, Japan. The variant-dominant periods comprised BA.1/BA.2 (sixth wave, January-June 2022), BA.5/BQ.1 (seventh-eighth waves, July 2022-March 2023), and XBB (ninth wave, April-December 2023). COVID-19 was diagnosed by rapid antigen testing.
Results: Among the 46,719 pediatric ED visits, 4,085 were COVID-19 cases; 599 (9.0%), 2,943 (15.4%) and 543 (2.6%) cases were diagnosed in the sixth, seventh-eighth, and ninth waves, respectively. During the XBB period, cough was significantly more frequent than in other periods and nasal discharge was more common compared with the BA.5/BQ.1 period. Vomiting occurred more frequently in the BA.5/BQ.1 period than in the BA.1/BA.2 period. Among children aged <1 year, vomiting was significantly more common during the XBB period. No significant differences were observed between patients aged 1-4 years. Dyspnea was more common in the BA.1/BA.2 than in the BA.5/BQ.1 period. In adolescents, fever occurred more frequently during the BA.5/BQ.1 period.
Conclusion: This study compared pediatric COVID-19 cases across the BA.1/BA.2, BA.5/BQ.1, and XBB waves. Although evidence for the XBB wave remains limited, upper respiratory symptoms such as nasal discharge and cough were observed more frequently during this period. Distinct differences in clinical presentations according to variant type and age group were identified.
Keywords: Coronavirus disease 2019 (COVID-19); Emergency department; Omicron; Pediatric; Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).