Clinical Characteristics of Seasonal Human Coronavirus Infections Among Children in the Post-COVID-19…

Cohort studyThe Pediatric infectious disease journal· Jul 2026

Clinical Characteristics of Seasonal Human Coronavirus Infections Among Children in the Post-COVID-19 Pandemic Era: A Retrospective Study Comparing HCoV Species and SARS-CoV-2 in Hokkaido, Japan, From April 2021 to September 2025.

Mayu Hachiya, Kenji Kondo, Hikaru Takahashi … Toshihiko Mori

Pediatric Infection & VaccinationCohort studyQ1IF 1.7

OC43 was the most common seasonal coronavirus species detected in children

Clinical Characteristics of Seasonal Human Coronavirus Infections Among Children in the Post-COVID-19 Pandemic Era: A Retrospective Study Comparing HCoV Species and SARS-CoV-2 in Hokkaido, Japan, From April 2021 to September 2025.

Mayu Hachiya … Toshihiko Mori

The Pediatric infectious disease journal · Jul 2026 · Q1 in Pediatrics

Background

Seasonal human coronaviruses (human coronaviruses) can cause acute respiratory infections in children; however, their epidemiology and clinical features in the post-coronavirus disease 2019 era remain incompletely characterized.

Methods

We retrospectively analyzed children under 16 years old with respiratory symptoms who underwent multiplex polymerase chain reaction testing at a hospital in Hokkaido, Japan, between April 2021 and September 2025.

n = 15,197 specimens

Results

OC43 accounted for more seasonal coronavirus detections than any other species

43.7%

OC43

31.5%

NL63

22.9%

HKU1

4.6%

229E

More results

Among 15,197 specimens, 1212 (8.0%) tested positive for human coronaviruses, including 361 (29.8%) single infections.

Among single human coronaviruses infections, the median age was 2.0 (interquartile range, 1.0-4.0) years, and 64.8% were male children.

More results

Upper respiratory infection was the most common diagnosis, and 14.7% of patients required hospitalization.

Compared with severe acute respiratory syndrome coronavirus 2, seasonal human coronaviruses infections occurred at younger ages and were more frequently associated with lower respiratory tract involvement, despite similar hospitalization rates.

“

Conclusion · 1 of 2

Seasonal patterns of human coronaviruses were temporarily altered during the coronavirus disease 2019 pandemic but returned to their pre-pandemic winter-spring predominance from 2023.

Conclusion · 2 of 2

Species-specific clinical differences were observed; compared with severe acute respiratory syndrome coronavirus 2, human coronaviruses infections occurred at younger ages and were more often associated with lower respiratory tract involvement.

Clinical Characteristics of Seasonal Human Coronavirus Infections Among Children in the Post-COVID-19 Pandemic Era: A Retrospective Study Comparing HCoV Species and SARS-CoV-2 in Hokkaido, Japan, From April 2021 to September 2025.

Clinical Characteristics of Seasonal Human Coronavirus Infections Among Children in the Post-COVID-19 Pandemic Era: A Retrospective Study Comparing HCoV Species and SARS-CoV-2 in Hokkaido, Japan, From April 2021 to September 2025.

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