Clinical manifestations, outcomes and prognostic factors of the 2009 pandemic influenza A (H1N1) in children

OBJECTIVE: To analyze the pandemic influenza A (H1N1) 2009 in children of the state of Paraná, Southern Brazil, in order to identify clinical features, lethality, and prognostic factors for the infection. METHODS: This was a retrospective observational study. Data were collected from the National Notifiable Disease System (Sinan) from the Brazilian Ministry of Health, from March to December, 2010. Children aged between zero and 12 years-old, with laboratorial confirmation of the infection, were included. Variables related to demographic and clinical characteristics and outcomes were evaluated statistically in order to compare the lethality rates in the presence and absence of these factors. The prognostic factors were identified by logistic regression, being significant p<0.05. RESULTS: 1,307 children were included and 19 of them died. Risk factors for death were heart diseases (OR 7.1; 95%CI 1.5 - 32.7), immunosuppression (OR 14.9; 95%CI 3.9 - 56.2), dyspnea (OR 9.5; 95%CI 2.8 - 32.9), pneumonia (OR 23.8; 95%CI 2.4 - 239.8), presence of wheezing (OR 11,9; 95%CI 1.4 - 103.7), and time to start treatment since the onset of symptoms (OR 1.3; 95%CI 1.2 - 1.5). Early treatment with the antiviral drug oseltamivir was a protective factor for death (OR 0.012; 95%CI 0.003 - 0.05). CONCLUSIONS: Underlying risk factors had a major role in determining outcomes. Early diagnosis and treatment were important for the reduction of deaths from influenza A (H1N1) 2009 in children.

Influenza A Virus, H1N1 Subtype; risk factors; lethality; signs and symptoms; child

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