ABSTRACT
BACKGROUND AND AIM: Flu is generally benign, although it can sometimes cause serious complications. The goal of the study was to describe the frequency, clinical evolution and complications of influenza in a PICU during five epidemic seasons. METHOD(S): Retrospective observational study of patients with influenza diagnosis admitted to PICU between 2015 and 2022. Demographic variables, morbidity, virus serotype, treatments, mortality and length of the PICU stay, were collected. RESULT(S): Twenty-five patients were admitted into the PICU for influenza, with a median age of 2 (IQR 2 - 6.5) years;52% were male and 40% had associated morbidity. Influenza A accounted for 80%, influenza B 12% and co-infection influenza A+B 8%. Bacterial co-infection was present in 20%, with the most common organisms being streptococcus pneumoniae and streptococcus pyogenes. We observed complications in 80% (sepsis/septic shock, bacterial pneumonia, pleural effusion, myocarditis, supraventricular tachycardia and seizures);64% received antibiotic therapy and 40% Oseltamivir. Non-invasive respiratory support was required in 48%, mechanical ventilation in 28% and inotropicvasopressor drugs in 20%. During the COVID-19 pandemic, there were no admissions for Influenza in the 2020-2021 season, and the first admission occurred in March 2022. Twenty-four months free of influenza were observed. During the study period, median PICU stay was 2 days [IQR 2 - 6.5]. Three children died (12%). CONCLUSION(S): We observed a high rate of complications and mortality, especially during the last SARS-COV-2 prepandemic season, since then we have only had 1 mild case admitted. Preventive measures against SARS-CoV-2 have probably contributed to reducing Influenza transmission.