[Epidemiologic description of a post-pandemic outbreak of influenza A H1N1 2009 in an isolated community of the region of Aysén, Chilean patagonia].

On August 10th 2010 the World Health Organization (WHO)announced the end of the influenza A H1N1 2009 pandemic. On August 13th, three cases of influenza A H1N1 2009 from the local school were confirmed at the Hospital de Chile Chico. An epidemiological investigation was conducted in conjunction with the regional health authority (SEREMI), in order to monitor the outbreak and establish appropriate control strategies. During the study period (august 7 to 21), 304 cases of influenza-like-illness (ILI) were reported, with an incidence of 6171 cases per 100.000 in epidemiological week no 33. Most of the affected people were 19 years old or younger (68% of cases). Hospitalized patients (n: 7) had a favorable outcome, without severe symptoms or need for transfer to an intensive care unit. A female patient with a congenital heart defect who had not been vaccinated was the only fatal case. The outstanding features of this post-pandemic outbreak were its intensity and the demonstration of the importance of control measures to prevent further spread of influenza A H1N1 2009 infections, in the community setting.