The invention provides methods for using virus-like particle (VLP) vaccines containing a stabilized pre-fusion respiratory syncytial virus (RSV) F protein to stimulate RSV neutralizing antibodies in pre-immune subjects. In one embodiment, the invention provides a method for immunizing a mammalian subject in need of immunizing against Respiratory Syncytial virus (RSV) infection, comprising, a) providing i) a pre-immune mammalian subject containing RSV neutralizing antibodies, ii) a first composition comprising recombinant chimeric Newcastle disease virus-like particles (ND VLPs), that contain a chimeric protein comprising, in operable combination, 1) stabilized pre-fusion RSV F protein ectodomain, 2) transmembrane (TM) domain of NDV F protein, and 3) cytoplasmic (CT) domain of NDV F protein, and b) administering an immunologically effective amount of the first composition to the pre-immune subject to produce an immunized subject that comprises an increase in the level of the RSV neutralizing antibodies compared to the level of RSV neutralizing antibodies in the pre-immune subject. In one embodiment, the level of the RSV neutralizing antibodies in the pre-immune subject does not prevent RSV infection of the pre-immune subject.L'invention concerne des procédés d'utilisation de vaccins à pseudo-particules virales (PPV) contenant une protéine F de pré-fusion stabilisée du virus respiratoire syncytial (VRS) pour stimuler la production d'anticorps neutralisant le VRS chez des sujets pré-immuns. Dans un mode de réalisation, l'invention concerne un procédé d'immunisation d'un sujet mammifère nécessitant une immunisation contre une infection par le virus respiratoire syncytial (VRS), comprenant : a) le recours i) à un sujet mammifère pré-immun abritant des anticorps neutralisant le VRS, ii) à une première composition comprenant des pseudo-particules virales chimères recombinées de la maladie de Newcastle (PPV MN), qui contiennent une protéine chimère comprenant, sous la forme
