Objectives: to analyze the prediction’s capacity of clinical symptoms to diagnose nH1N1 Influenza in outpatients who were chosen by Aragon’s Sentinel surveillance Network. To compare outpatients with hospitalized cases during influenza A virus pandemic (2009-2010).
Methods: retrospective study of a randomized group of patients with symptoms of influenza who had laboratory-confirmation by PCR-RT and of all patients admitted to the reference hospital of Aragon. Comparison of epidemiological and clinical characteristics in outpatients and between outpatients and hospital cases.
Results: there were no clinical differences between the laboratory-confirmed by PCR-RT cases and the other outpatients, so it was not possible to find defining symptoms of infection. Hospitalized patients were younger, with higher percentage of underlying disease and comorbidity.
Conclusions: the epidemic of influenza A behaved as a benign disease, symptoms were similar to seasonal influenza. The clinical finding of having influenza symptoms in a high incidence week (weeks 43-48) was moderately predictive of influenza A infection.
Keywords: Epidemiological surveillance. Epidemiology. Influenza, Human. Signs and symptoms. Primary Care. Outpatients. Influenza A Virus, nH1N1 Subtype.