The year 2009 was marked by the outbreak of the influenza A(H1N1)pdm09 pandemic. This epidemic, which spread very rapidly and widely on an international scale, was characterized by the exclusive circulation of the A(H1N1)pdm09 virus, to the exclusion of other influenza viruses. The clinical manifestations in infected patients were, in most cases, fairly mild, and in some instances even completely asymptomatic. [...]