Influenza outbreak We seem to be heading for a big flu outbreak. NAC has been shown to attentuate flu symptoms. [Eur Respir J. 1997 Jul;10(7):1535-41.Attenuation of influenza-like symptomatology and improvement of cell-mediated immunity with long-term N-acetylcysteine treatment. De Flora S1, Grassi C, Carati L.] These authors comment: “Administration of N-acetylcysteine during the winter, thus, appears to provide a significant attenuation of influenza and influenza-like episodes, especially in elderly high-risk individuals.