The present invention in particular relates to a method of producing animmunogenic composition exhibiting reducedvirucidal activity, as well as to the immunogenic composition and usesthereof, wherein the method in particular comprises the stepsof: (a) providing a mixture with a first liquid and a recombinant protein, (b)concentrating the recombinant protein in the mixture byremoving a portion of the first liquid from the mixture, and (c) processingthe solution resulting from step (b) by continuous diafiltration.