The invention pertains to a protein having at least 69% sequence identity with the protein according to SEQ ID No: 1 or an immunogenic fragment of this protein, for use in a prophylactic method to protect a pig against an infection with Haemophilus parasuis by administering a vaccine to the pig, the vaccine comprising the protein or the immunogenic fragment thereof as an antigen. The invention also pertains to a vaccine, a method to manufacture such a vaccine and a method to protect a pig against H. parasuis.