Influenza.

Influenza is a disease of global public health significance as evidenced by the 2009 pandemic caused by a novel swine-origin H1N1 virus. Influenza epidemics occur almost every year and are less striking, but nevertheless, account for considerable morbidity and school absences among healthy children and adolescents. Patients with chronic conditions may develop severe illness. This article discusses the epidemiology, clinical manifestations, diagnosis, and management of influenza. Vaccination is the most effective measure available for the control of influenza. Recommendations for use of the inactivated and live attenuated vaccines against seasonal influenza and against the 2009 novel H1N1 influenza viruses are reviewed.