Bermejo-Martin, Jesus FKelvin, David JGuan, YiChen, HonglinPerez-Breña, PilarCasas Flecha, InmaculadaArranz, Eduardode Lejarazu, Raul O2021-01-152021-01-152007-06PLoS Med . 2007 Jun;4(6):e212. dhttp://hdl.handle.net/20.500.12105/11614We have read with great interest the work of Sandbulte et al. recently published in your journal [1]. In this article, the authors provide evidence for the existence of cross-immunity between the neuraminidase of H5N1 viruses and that of endemic human H1N1 viruses. Age may be an important determining factor in the development of cross-immunity: younger people, having a shorter history of H1N1 exposure, may be disproportionately susceptible to H5N1 infection.engVoRAnimalsAntibodies, ViralDisease OutbreaksHumansInfluenza A Virus, H5N1 SubtypeInfluenza VaccinesInfluenza, HumanMiceNeuraminidaseOrthomyxoviridae InfectionsAtribución 4.0 Internacional1759389746e21210.1371/journal.pmed.00402121549-1676PLoS medicineopen access