On January 14, 2021, a state of emergency was declared in Osaka Prefecture owing to the Coronavirus disease-2019 (COVID-19) pandemic. However, as the number of patients decreased, lifting the state of emergency was proposed. After the emergency declaration was lifted, the number of patients with COVID-19 and severe COVID-19 in Osaka Prefecture increased rapidly. In Osaka Prefecture, the presence of the VOC 202012/01 variant was confirmed on February 22, 2021. As this variant contributes to a higher risk of death than the conventional strains, this study investigated change in the age range of patients with severe COVID-19, in Osaka with a rapidly growing population before and after the emergency declaration. The study included two periods: December 14, 2020, to January 13, 2021 (Period A: before the declaration) and March 8, 2021, to April 7, 2021 (Period B: after the declaration). Data were collected and analyzed to compare the proportions of severely ill COVID-19 patients in different age ranges and the presence or absence of primary illnesses in them between Periods A and B. The results showed that a higher proportion of younger individuals (aged <60 years) in Osaka had severe COVID-19 in Period B than in Period A. We must be more diligent in implementing infection control measures than before. Any change in infectivity and severity should be monitored in patients infected with VOC 202012/01 and conventional severe acute respiratory syndrome-Coronavirus-2 in Osaka.
Change in the Age Range of Patients with Severe COVID-19 in Osaka before and after the State of Emergency Declaration