The Role of COVID-19 Vaccinal Status in Admitted Children during OMICRON Variant Circulation in Rio de Janeiro, City—Preliminary Report

Objective: To evaluate COVID-19 vaccination status in admitted children in 2020–2021 and during the OMICRON variant circulation (2022), a period when children older than 12 years of age had received two doses of COVID-19 vaccines. Design: An observational retrospective study. Patients with confirmed COVID-19 were compared in two different periods: 2020–2021 when adolescents aged 12–18 years had not received the complete COVID-19 vaccine, and 2022 when children older than 12 years had received the complete Pfizer-BioNTech vaccine scheme. Setting: Two pediatric hospitals in Rio de Janeiro city. Patients: Children aged < 18 years with confirmed COVID-19. Intervention: None. Main outcome: Vaccination status for COVID-19 on admission. Results: In total, 300 patients were admitted with confirmed COVID-19 (240 in 2020–2021 and 60 in 2022). The distribution of patients according to the age-groups was: 0–2 years (33.3% in 2020–2021 and 53.4% in 2022), 2–5 years (21.7% in 2020–2021 and 10% in 2022), 5–11 years (29.2% in 2020–2021 and 28.3% in 2022), and 12–18 years (15.8% in 2020–2021 and 8.3% in 2022) (p = 0.076). The median length of stay was six days in 2020–2021 and six days in 2022 (p = 0.423). We verified six deaths in the first analysis period and one death in the second one (p = 0.894). Of the 60 children admitted in 2022, 58 (96.7%) did not receive the complete COVID-19 vaccine scheme available. Conclusions: We verified in a “real-world condition” the ability of the Pfizer-BioNTech vaccine to prevent hospitalization in children over 12 years of age.