A method for immunising a human subject, wherein the subject receives (i) an immunogenic composition comprising bacterial vesicles and (ii) an antipyretic, and wherein the immunogenic composition and the antipyretic are administered to the subject within 24 hours of each other. Paracetamol significantly reduces fever rates without negatively affecting the immunogenicity either of a meningococcal vesicle vaccine or of concomitantly-administered antigens.
