Table 1

Change in the number of paediatric hospitalisations during the COVID-19 outbreak in Japan

Condition*No. of hospitalisations per week†Difference between 2017–2019 and 2020Adjusted incidence rate ratio‡
Weeks 9–21 of 2017–2019Weeks 9–21 of 2020Count% changeEstimate95% CIP value
Acute lower respiratory infections379145−235−61.90.390.26 to 0.58<0.001
Intestinal infectious disease20949−160− to 0.29<0.001
Trauma199136−63−31.90.680.61 to 0.75<0.001
Asthma12036−84−69.70.370.29 to 0.47<0.001
Food allergy119103−16−13.10.610.52 to 0.70<0.001
Kawasaki disease5842−16−27.40.770.67 to 0.89<0.001
Appendicitis4945-4−8.90.960.82 to 1.120.59
Febrile convulsions4228−14−33.20.690.57 to 0.84<0.001
Inguinal hernia3430-4−12.20.800.67 to 0.950.01
Total21321314−818−38.40.600.53 to 0.69<0.001
  • *International Classification of Diseases Tenth Revision codes for the conditions were: A37, B012, B052, B59, B371, J9–J18 and J20–J22 (acute lower respiratory infections), A00–A09 (intestinal infectious diseases), S00–S99 and T00–T14 (trauma), J45 and J46 (asthma), T780 and T781 (food allergy), M303 (Kawasaki disease), K35–K37 (appendicitis), R560 (febrile convulsions) and K40 (inguinal hernia).

  • †The numbers of hospitalisations were shown as a weekly mean over the corresponding weeks.

  • ‡A Poisson regression was applied to estimate adjusted incidence rate ratio with the weekly and the yearly trends adjusted. Huber-White SEs were used for inference. P<0.05 was interpreted as statistically significant (Stata V.16.1).