Introduction
Since the beginning of the pandemic, epidemiologic data have shown that
hospitalization of children and adolescents associated with the severe
acute respiratory syndrome (SARS) due to COVID -19 has not significantly
impacted this population. They differ from the elderly and adult
population with comorbidities, which are specially more susceptible to
severe disease progression and complications. (1)
In children, several factors contributed to milder infection, which
reduces the number of the significant receptor angiotensin-converting
enzyme 2 (ACE2) on the cell surface, resulting in less availability of
the receptor, and the presence of other respiratory viruses competing
simultaneously and limiting replication of different viruses. In
neonates and infants, maternal antibodies provide protective immunity
against disease (2,3).
In Brazil, the incidence of SARS associated with COVID -19 totaled
20.846 cases and 856 deaths in the age group between 0 and 19 years by
epidemiological week 51 of 2022 (3). In this context, it can also be
observed that children were not initially affected by SARS-CoV-2 as much
as in the 2009 pandemic caused by H1N1. (4)
It should be noted that the government took several preventive measures
to reduce transmission rates in the early stages of the pandemic and
after the initial outbreak in Brazil. This dramatically impacted the
child population, as schools were closed and classes moved to remote
locations, as well as the introduction of social distancing (lockdown),
the use of masks, increased availability of Covid-19 testing, and the
establishment of field hospitals.
However, after two years of the pandemic, the return of social
activities, and the emergence of new variants, among other factors such
as mass vaccination of the adult population and the characterization of
a new variant of concern called Ômicron in late 2021, there has been an
increase in confirmed cases of hospitalized children associated with
this new variant and its subtype.