Epidemiological and clinical profile between influenza A and B virus in Costa Rican children.

ABSTRACT

OBJECTIVE: We aimed to evaluate the clinical and epidemiological behavior of influenza type A versus type B and analyze if there was any correlation or differences between the characteristics of both groups. METHODS: An observational, retrospective, descriptive, and population-based study based of children who were hospitalized at the only national pediatric hospital of Costa Rica from January 1, 2010 to December 31, 2018 and had a confirmed influenza virus infection. RESULTS: 336 patients were analyzed. Mean age was 35,6 ± 36,7 months (3,0 ± 3,1 years). The only significant variables at 25% in relation to influenza type A or B virus were sex, month of diagnosis, fever, vomiting, cough, use of antibiotics and admission to the PICU. The hospitalization rate at our hospital increased between the months of October to December, with a higher percentage of cases in November and December, which reveals that the "real peak" in our population begins between 3 to 4 months after the end of the vaccination campaign. Patients with influenza A virus had a 2.5 times greater risk of being admitted to the PICU. Mortality rate was 0.6% and 0% among influenza A and B children, respectively. CONCLUSIONS: Variables in which a causality was found with type A or B virus were admission to the PICU, month of diagnosis, and cough. However, influenza B clinical behavior continues to be unpredictable.