Has the age distribution of hospitalized Covid-19 patients changed in Brazil?

The aim of this study was to compare the age profile of hospitalized Covid-19 patients during the first year of the pandemic, as well as hospital mortality and use of ICUs, by age group, in large geographic regions of Brazil. We used data from the Influenza Epidemiological Surveillance Information System for patients who presented the first symptoms of the disease between the epidemiological weeks 8 of 2020 and 7 of 2021, which were divided into three periods. 779,257 records of patients hospitalized by Covid-19 were obtained. Of this total, 720,363 (92.4%) referred to discharged hospitalizations, considered in the analysis of ICU use and death. Among 244,611 hospitalizations (34.0%) with indication for use of ICU, 190,833 allowed the calculation of the time in ICU. There was variation in the age profile of hospitalized patients between the three periods, but there was no evidence in favor of the hypothesis of an increase, in the last period, in the participation of adults between 18 and 50 years old in hospitalizations by Covid-19. A differentiated increase in the mortality of young adults in the North suggests the possibility of greater severity of the P1 variant in this population. The results also show that the participation of young adults in hospitalizations and hospital deaths was never negligible and is related to hospital mortality rates close to or above 10%. The Covid-19 "youthening" phenomenon in Brazil is based on the countrys own sociodemographic and economic characteristics and may have been strengthened by the increasing circulation of viral variants. It is important to continue monitoring its progression and effects.